Lighthouse: Transfer Size in keep request counts low and transfer sizes small diagnostic is incorrect

[lucacasonato]

Provide the steps to reproduce

1. Run LH on https://test.lucacasonato.vercel.app/
2. View Keep request counts low and transfer sizes small diagnostics

What is the current behavior?

The Transfer Size is not correct. It is double, triple, quadruple, or 10 fold the actual value:
It says 0.5 kb for Script in Lighthouse

vs 48 bytes in network panel:

Here is a JSON export from Lighthouse on this page: test.lucacasonato.vercel.app-20200911T201026.txt

What is the expected behavior?

I expect Lighthouse to show the correct values.

Environment Information

• Affected Channels: DevTools
• Lighthouse version: 6.3.0
• Chrome version: 87.0.4259.3 (Official Build) dev (64-bit)>
• Operating System: Linux

[patrickhulce]

Thanks for filing @lucacasonato!

That screenshot is of the transfer sizes of empty 304 Not Modified responses though (which are obviously smaller than the resources themselves).

The transfer sizes will not exactly match regular DevTools network panel when the server varies its response or headers when requested by the Lighthouse UA (which this page seems to do).

Additionally, this page seems to have non-deterministic payload sizes, so different page loads will not even match each other in devtools.

[lucacasonato]

@patrickhulce Thanks for the quick response.

Right - those 304's are obviously smaller. I have another page with a larger script that is around ~50K, but lighthouse displays it as 90KB. I can confirm the actual size + headers with curl -i <url> -H "User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36(KHTML, like Gecko) Chrome/61.0.3116.0 Safari/537.36 Chrome-Lighthouse" | wc -c. I will get you a public URL shortly.

[lucacasonato]

@patrickhulce Unfortunately I can not share the actual URL this is occurring on publicly right now. I also can't get a minimal reproduction to produce the issue.

I tested some random sites though, and it seems the same issue is visible on vercel.com (to a lesser extent though):
1057 KB on lighthouse,

but only ~798KB in transferred JS in network tools:

I don't think the 260KB disparity comes from headers here. What am I missing?

[connorjclark]

Is the Lighthouse report a mobile or desktop run? Is the devtools Network screenshot from desktop (no emulation) or mobile emulation?

You might be able to a do a request-by-request comparison if you look at the network-requests audit in the report (export to JSON via the top right menu to see the data, it's not visible in the html)

[lucacasonato]

Network tools is no emulation. Lighthouse is desktop with simulated throttling disabled (same occurs with throttling though).

You might be able to a do a request-by-request comparison if you look at the network-requests audit in the report (export to JSON via the top right menu to see the data, it's not visible in the html)

Just looking at https://vercel.com/_next/static/chunks/main-9e0fb335dda8ca54808e.js network tools reports 10.2KB transferred, Lighthouse JSON reports 18926 bytes. curl reports 11281 bytes with headers (brotli, with lh ua)

[connorjclark]

Does this site do any sort of polyfilling based on the UA?

[connorjclark]

I see the same on https://www.paulirish.com/ , but for resourceSize (transferSize is correct)

I get the expected size from the CLI (current master and v6).

[lucacasonato]

Does this site do any sort of polyfilling based on the UA?

Not that I am aware. Only feature detection based polyfilling AFAIK. The non-public page that has this same issue definitely does not.

I get the expected size from the CLI (current master and v6).

Same here - the file sizes are correct on CLI.

This might be specific to the DevTools client.

Should I re-file this again at https://crbug.com, or is there an easier way to move this issue there?

[connorjclark]

Should I re-file this again at crbug.com, or is there an easier way to move this issue there?

No, it's best here.

[connorjclark]

For Paul's example, I noticed in CLI I get two dataReceived events for that request. The first is 63390 bytes. the second is zero. The incorrect value that Lighthouse gets in devtools is 126780, which is 63390 * 2.

I believe I summarized the behavior of dataReceived in a previous PR, I'll have to comb through this file's history to find it. But I can definitely confirm this is a bug in Lighthouse' DevTools integration.

[connorjclark]

Got the devtools log from Lighthouse panel. Filtered to just a single request id.

[
  {
    "method": "Network.requestWillBeSent",
    "params": {
      "requestId": "20547.527",
      "loaderId": "03AA98C42439D20FB683B20B550D35B1",
      "documentURL": "https://www.paulirish.com/",
      "request": {
        "url": "https://www.paulirish.com/javascripts/firebase-performance.js",
        "method": "GET",
        "headers": {
          "Referer": "https://www.paulirish.com/",
          "User-Agent": "Mozilla/5.0 (Linux; Android 7.0; Moto G (4)) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4143.7 Mobile Safari/537.36 Chrome-Lighthouse"
        },
        "mixedContentType": "none",
        "initialPriority": "Low",
        "referrerPolicy": "strict-origin-when-cross-origin"
      },
      "timestamp": 572120.631581,
      "wallTime": 1599868505.911691,
      "initiator": {
        "type": "script",
        "stack": {
          "callFrames": [
            {
              "functionName": "load",
              "scriptId": "250",
              "url": "https://www.paulirish.com/",
              "lineNumber": 21,
              "columnNumber": 13
            },
            {
              "functionName": "",
              "scriptId": "250",
              "url": "https://www.paulirish.com/",
              "lineNumber": 21,
              "columnNumber": 52
            }
          ],
          "parent": {
            "description": "load",
            "callFrames": [
              {
                "functionName": "load",
                "scriptId": "250",
                "url": "https://www.paulirish.com/",
                "lineNumber": 20,
                "columnNumber": 26
              },
              {
                "functionName": "",
                "scriptId": "250",
                "url": "https://www.paulirish.com/",
                "lineNumber": 21,
                "columnNumber": 32
              },
              {
                "functionName": "",
                "scriptId": "250",
                "url": "https://www.paulirish.com/",
                "lineNumber": 23,
                "columnNumber": 2
              }
            ]
          }
        }
      },
      "type": "Script",
      "frameId": "596848B1492407A0F98476021D11CFA2",
      "hasUserGesture": false
    }
  },
  {
    "method": "Network.requestWillBeSent",
    "params": {
      "requestId": "20547.527",
      "loaderId": "03AA98C42439D20FB683B20B550D35B1",
      "documentURL": "https://www.paulirish.com/",
      "request": {
        "url": "https://www.paulirish.com/javascripts/firebase-performance.js",
        "method": "GET",
        "headers": {
          "Referer": "https://www.paulirish.com/",
          "User-Agent": "Mozilla/5.0 (Linux; Android 7.0; Moto G (4)) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4143.7 Mobile Safari/537.36 Chrome-Lighthouse"
        },
        "mixedContentType": "none",
        "initialPriority": "Low",
        "referrerPolicy": "strict-origin-when-cross-origin"
      },
      "timestamp": 572120.631651,
      "wallTime": 1599868505.911762,
      "initiator": {
        "type": "script",
        "stack": {
          "callFrames": [
            {
              "functionName": "load",
              "scriptId": "250",
              "url": "https://www.paulirish.com/",
              "lineNumber": 21,
              "columnNumber": 13
            },
            {
              "functionName": "",
              "scriptId": "250",
              "url": "https://www.paulirish.com/",
              "lineNumber": 21,
              "columnNumber": 52
            }
          ],
          "parent": {
            "description": "load",
            "callFrames": [
              {
                "functionName": "load",
                "scriptId": "250",
                "url": "https://www.paulirish.com/",
                "lineNumber": 20,
                "columnNumber": 26
              },
              {
                "functionName": "",
                "scriptId": "250",
                "url": "https://www.paulirish.com/",
                "lineNumber": 21,
                "columnNumber": 32
              },
              {
                "functionName": "",
                "scriptId": "250",
                "url": "https://www.paulirish.com/",
                "lineNumber": 23,
                "columnNumber": 2
              }
            ]
          }
        }
      },
      "type": "Script",
      "frameId": "596848B1492407A0F98476021D11CFA2",
      "hasUserGesture": false
    },
    "sessionId": "10028EC926C319C7F1E31B88D72B15AE"
  },
  {
    "method": "Network.requestWillBeSentExtraInfo",
    "params": {
      "requestId": "20547.527",
      "associatedCookies": [
        {
          "blockedReasons": [],
          "cookie": {
            "name": "_ga",
            "value": "GA1.2.1729210066.1594753805",
            "domain": ".paulirish.com",
            "path": "/",
            "expires": 1662940484,
            "size": 30,
            "httpOnly": false,
            "secure": false,
            "session": false,
            "priority": "Medium"
          }
        },
        {
          "blockedReasons": [],
          "cookie": {
            "name": "__cfduid",
            "value": "d42e6b6800303a1fbd3cf7c0fe6b4f0fa1597940207",
            "domain": ".paulirish.com",
            "path": "/",
            "expires": 1600532207.550761,
            "size": 51,
            "httpOnly": true,
            "secure": false,
            "session": false,
            "sameSite": "Lax",
            "priority": "Medium"
          }
        },
        {
          "blockedReasons": [],
          "cookie": {
            "name": "_gid",
            "value": "GA1.2.1000049010.1599865894",
            "domain": ".paulirish.com",
            "path": "/",
            "expires": 1599954884,
            "size": 31,
            "httpOnly": false,
            "secure": false,
            "session": false,
            "priority": "Medium"
          }
        },
        {
          "blockedReasons": [],
          "cookie": {
            "name": "_gat",
            "value": "1",
            "domain": ".paulirish.com",
            "path": "/",
            "expires": 1599868519,
            "size": 5,
            "httpOnly": false,
            "secure": false,
            "session": false,
            "priority": "Medium"
          }
        }
      ],
      "headers": {
        ":method": "GET",
        ":authority": "www.paulirish.com",
        ":scheme": "https",
        ":path": "/javascripts/firebase-performance.js",
        "user-agent": "Mozilla/5.0 (Linux; Android 7.0; Moto G (4)) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4143.7 Mobile Safari/537.36 Chrome-Lighthouse",
        "accept": "*/*",
        "sec-fetch-site": "same-origin",
        "sec-fetch-mode": "no-cors",
        "sec-fetch-dest": "script",
        "referer": "https://www.paulirish.com/",
        "accept-encoding": "gzip, deflate, br",
        "accept-language": "en-US,en;q=0.9",
        "cookie": "_ga=GA1.2.1729210066.1594753805; __cfduid=d42e6b6800303a1fbd3cf7c0fe6b4f0fa1597940207; _gid=GA1.2.1000049010.1599865894; _gat=1"
      }
    }
  },
  {
    "method": "Network.requestWillBeSentExtraInfo",
    "params": {
      "requestId": "20547.527",
      "associatedCookies": [
        {
          "blockedReasons": [],
          "cookie": {
            "name": "_ga",
            "value": "GA1.2.1729210066.1594753805",
            "domain": ".paulirish.com",
            "path": "/",
            "expires": 1662940484,
            "size": 30,
            "httpOnly": false,
            "secure": false,
            "session": false,
            "priority": "Medium"
          }
        },
        {
          "blockedReasons": [],
          "cookie": {
            "name": "__cfduid",
            "value": "d42e6b6800303a1fbd3cf7c0fe6b4f0fa1597940207",
            "domain": ".paulirish.com",
            "path": "/",
            "expires": 1600532207.550761,
            "size": 51,
            "httpOnly": true,
            "secure": false,
            "session": false,
            "sameSite": "Lax",
            "priority": "Medium"
          }
        },
        {
          "blockedReasons": [],
          "cookie": {
            "name": "_gid",
            "value": "GA1.2.1000049010.1599865894",
            "domain": ".paulirish.com",
            "path": "/",
            "expires": 1599954884,
            "size": 31,
            "httpOnly": false,
            "secure": false,
            "session": false,
            "priority": "Medium"
          }
        },
        {
          "blockedReasons": [],
          "cookie": {
            "name": "_gat",
            "value": "1",
            "domain": ".paulirish.com",
            "path": "/",
            "expires": 1599868519,
            "size": 5,
            "httpOnly": false,
            "secure": false,
            "session": false,
            "priority": "Medium"
          }
        }
      ],
      "headers": {
        ":method": "GET",
        ":authority": "www.paulirish.com",
        ":scheme": "https",
        ":path": "/javascripts/firebase-performance.js",
        "user-agent": "Mozilla/5.0 (Linux; Android 7.0; Moto G (4)) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4143.7 Mobile Safari/537.36 Chrome-Lighthouse",
        "accept": "*/*",
        "sec-fetch-site": "same-origin",
        "sec-fetch-mode": "no-cors",
        "sec-fetch-dest": "script",
        "referer": "https://www.paulirish.com/",
        "accept-encoding": "gzip, deflate, br",
        "accept-language": "en-US,en;q=0.9",
        "cookie": "_ga=GA1.2.1729210066.1594753805; __cfduid=d42e6b6800303a1fbd3cf7c0fe6b4f0fa1597940207; _gid=GA1.2.1000049010.1599865894; _gat=1"
      }
    },
    "sessionId": "10028EC926C319C7F1E31B88D72B15AE"
  },
  {
    "method": "Network.responseReceivedExtraInfo",
    "params": {
      "requestId": "20547.527",
      "blockedCookies": [],
      "headers": {
        "status": "200",
        "date": "Fri, 11 Sep 2020 23:55:06 GMT",
        "content-type": "application/javascript",
        "cache-control": "max-age=2592000",
        "cf-bgj": "minify",
        "cf-polished": "origSize=64047",
        "content-security-policy": "default-src 'self' https://c.disquscdn.com https://disqus.com; script-src 'self' 'unsafe-inline' https://ssl.google-analytics.com https://api.github.com https://disqus.com https://go.disqus.com https://*.disquscdn.com https://www.google-analytics.com https://paulirish.disqus.com https://platform.twitter.com https://cdn.syndication.twimg.com; style-src 'self' 'unsafe-inline' https://fonts.googleapis.com https://platform.twitter.com; img-src * 'self' data:; font-src 'self' data: https://fonts.gstatic.com; connect-src 'self' https://firebaseinstallations.googleapis.com https://firebaselogging.googleapis.com  https://firebaseremoteconfig.googleapis.com https://www.google-analytics.com; media-src; object-src; prefetch-src *; child-src; frame-src 'self' https://platform.twitter.com https://accounts.google.com https://player.vimeo.com https://www.youtube.com https://apis.google.com https://disqus.com https://paulirish.wufoo.com;  upgrade-insecure-requests;report-uri https://paulirish.report-uri.com/r/d/csp/enforce;",
        "etag": "W/\"fa2f-5ac786f01df80\"",
        "expires": "Thu, 17 Sep 2020 13:38:56 GMT",
        "last-modified": "Sun, 09 Aug 2020 21:22:22 GMT",
        "vary": "Accept-Encoding,User-Agent",
        "cf-cache-status": "HIT",
        "age": "1935574",
        "cf-request-id": "05213128450000feae0c956200000001",
        "expect-ct": "max-age=604800, report-uri=\"https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct\"",
        "server": "cloudflare",
        "cf-ray": "5d155153abf0feae-IAH",
        "content-encoding": "br"
      }
    }
  },
  {
    "method": "Network.responseReceivedExtraInfo",
    "params": {
      "requestId": "20547.527",
      "blockedCookies": [],
      "headers": {
        "status": "200",
        "date": "Fri, 11 Sep 2020 23:55:06 GMT",
        "content-type": "application/javascript",
        "cache-control": "max-age=2592000",
        "cf-bgj": "minify",
        "cf-polished": "origSize=64047",
        "content-security-policy": "default-src 'self' https://c.disquscdn.com https://disqus.com; script-src 'self' 'unsafe-inline' https://ssl.google-analytics.com https://api.github.com https://disqus.com https://go.disqus.com https://*.disquscdn.com https://www.google-analytics.com https://paulirish.disqus.com https://platform.twitter.com https://cdn.syndication.twimg.com; style-src 'self' 'unsafe-inline' https://fonts.googleapis.com https://platform.twitter.com; img-src * 'self' data:; font-src 'self' data: https://fonts.gstatic.com; connect-src 'self' https://firebaseinstallations.googleapis.com https://firebaselogging.googleapis.com  https://firebaseremoteconfig.googleapis.com https://www.google-analytics.com; media-src; object-src; prefetch-src *; child-src; frame-src 'self' https://platform.twitter.com https://accounts.google.com https://player.vimeo.com https://www.youtube.com https://apis.google.com https://disqus.com https://paulirish.wufoo.com;  upgrade-insecure-requests;report-uri https://paulirish.report-uri.com/r/d/csp/enforce;",
        "etag": "W/\"fa2f-5ac786f01df80\"",
        "expires": "Thu, 17 Sep 2020 13:38:56 GMT",
        "last-modified": "Sun, 09 Aug 2020 21:22:22 GMT",
        "vary": "Accept-Encoding,User-Agent",
        "cf-cache-status": "HIT",
        "age": "1935574",
        "cf-request-id": "05213128450000feae0c956200000001",
        "expect-ct": "max-age=604800, report-uri=\"https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct\"",
        "server": "cloudflare",
        "cf-ray": "5d155153abf0feae-IAH",
        "content-encoding": "br"
      }
    },
    "sessionId": "10028EC926C319C7F1E31B88D72B15AE"
  },
  {
    "method": "Network.responseReceived",
    "params": {
      "requestId": "20547.527",
      "loaderId": "03AA98C42439D20FB683B20B550D35B1",
      "timestamp": 572121.539472,
      "type": "Script",
      "response": {
        "url": "https://www.paulirish.com/javascripts/firebase-performance.js",
        "status": 200,
        "statusText": "",
        "headers": {
          "date": "Fri, 11 Sep 2020 23:55:06 GMT",
          "content-encoding": "br",
          "cf-cache-status": "HIT",
          "age": "1935574",
          "cf-polished": "origSize=64047",
          "status": "200",
          "cf-request-id": "05213128450000feae0c956200000001",
          "last-modified": "Sun, 09 Aug 2020 21:22:22 GMT",
          "server": "cloudflare",
          "etag": "W/\"fa2f-5ac786f01df80\"",
          "expect-ct": "max-age=604800, report-uri=\"https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct\"",
          "vary": "Accept-Encoding,User-Agent",
          "content-type": "application/javascript",
          "expires": "Thu, 17 Sep 2020 13:38:56 GMT",
          "cache-control": "max-age=2592000",
          "content-security-policy": "default-src 'self' https://c.disquscdn.com https://disqus.com; script-src 'self' 'unsafe-inline' https://ssl.google-analytics.com https://api.github.com https://disqus.com https://go.disqus.com https://*.disquscdn.com https://www.google-analytics.com https://paulirish.disqus.com https://platform.twitter.com https://cdn.syndication.twimg.com; style-src 'self' 'unsafe-inline' https://fonts.googleapis.com https://platform.twitter.com; img-src * 'self' data:; font-src 'self' data: https://fonts.gstatic.com; connect-src 'self' https://firebaseinstallations.googleapis.com https://firebaselogging.googleapis.com  https://firebaseremoteconfig.googleapis.com https://www.google-analytics.com; media-src; object-src; prefetch-src *; child-src; frame-src 'self' https://platform.twitter.com https://accounts.google.com https://player.vimeo.com https://www.youtube.com https://apis.google.com https://disqus.com https://paulirish.wufoo.com;  upgrade-insecure-requests;report-uri https://paulirish.report-uri.com/r/d/csp/enforce;",
          "cf-ray": "5d155153abf0feae-IAH",
          "cf-bgj": "minify"
        },
        "mimeType": "application/javascript",
        "requestHeaders": {
          ":path": "/javascripts/firebase-performance.js",
          "sec-fetch-mode": "no-cors",
          "accept-encoding": "gzip, deflate, br",
          "accept-language": "en-US,en;q=0.9",
          "user-agent": "Mozilla/5.0 (Linux; Android 7.0; Moto G (4)) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4143.7 Mobile Safari/537.36 Chrome-Lighthouse",
          "accept": "*/*",
          "referer": "https://www.paulirish.com/",
          "sec-fetch-dest": "script",
          ":authority": "www.paulirish.com",
          "cookie": "_ga=GA1.2.1729210066.1594753805; __cfduid=d42e6b6800303a1fbd3cf7c0fe6b4f0fa1597940207; _gid=GA1.2.1000049010.1599865894; _gat=1",
          ":scheme": "https",
          "sec-fetch-site": "same-origin",
          ":method": "GET"
        },
        "connectionReused": true,
        "connectionId": 9012,
        "remoteIPAddress": "104.28.23.33",
        "remotePort": 443,
        "fromDiskCache": false,
        "fromServiceWorker": false,
        "fromPrefetchCache": false,
        "encodedDataLength": 20442,
        "timing": {
          "requestTime": 572120.888558,
          "proxyStart": 0.389,
          "proxyEnd": 0.635,
          "dnsStart": -1,
          "dnsEnd": -1,
          "connectStart": -1,
          "connectEnd": -1,
          "sslStart": -1,
          "sslEnd": -1,
          "workerStart": -1,
          "workerReady": -1,
          "workerFetchStart": -1,
          "workerRespondWithSettled": -1,
          "sendStart": 0.705,
          "sendEnd": 0.82,
          "pushStart": 0,
          "pushEnd": 0,
          "receiveHeadersEnd": 602.698
        },
        "responseTime": 1599868506191.166,
        "protocol": "h2",
        "securityState": "secure",
        "securityDetails": {
          "protocol": "TLS 1.3",
          "keyExchange": "",
          "keyExchangeGroup": "X25519",
          "cipher": "AES_128_GCM",
          "certificateId": 0,
          "subjectName": "sni.cloudflaressl.com",
          "sanList": [
            "paulirish.com",
            "sni.cloudflaressl.com",
            "*.paulirish.com"
          ],
          "issuer": "Cloudflare Inc ECC CA-3",
          "validFrom": 1595548800,
          "validTo": 1627128000,
          "signedCertificateTimestampList": [
            {
              "status": "Verified",
              "origin": "Embedded in certificate",
              "logDescription": "Google 'Argon2021' log",
              "logId": "F65C942FD1773022145418083094568EE34D131933BFDF0C2F200BCC4EF164E3",
              "timestamp": 1595567700006,
              "hashAlgorithm": "SHA-256",
              "signatureAlgorithm": "ECDSA",
              "signatureData": "304502201E5CE83AA7BAE618403970F57D84CA4A9C511EE06062322FB70F6CE12AC8832002210094815E1767254B1EA7DDD9AAB3618BF4F293315E744F1449B0D716B3E7A92848"
            },
            {
              "status": "Verified",
              "origin": "Embedded in certificate",
              "logDescription": "DigiCert Yeti2021 Log",
              "logId": "5CDC4392FEE6AB4544B15E9AD456E61037FBD5FA47DCA17394B25EE6F6C70ECA",
              "timestamp": 1595567700057,
              "hashAlgorithm": "SHA-256",
              "signatureAlgorithm": "ECDSA",
              "signatureData": "3045022100FC2DCFCFB1EC2C64EC36A6E75938B8C49AD124BD0CC96F16B334E8FE7C9CB6400220609D434E61CD7A92413709FB2038950F368541DCD1BAD4118BB80B0528E85724"
            }
          ],
          "certificateTransparencyCompliance": "compliant"
        }
      },
      "frameId": "596848B1492407A0F98476021D11CFA2"
    }
  },
  {
    "method": "Network.responseReceived",
    "params": {
      "requestId": "20547.527",
      "loaderId": "03AA98C42439D20FB683B20B550D35B1",
      "timestamp": 572121.539523,
      "type": "Script",
      "response": {
        "url": "https://www.paulirish.com/javascripts/firebase-performance.js",
        "status": 200,
        "statusText": "",
        "headers": {
          "date": "Fri, 11 Sep 2020 23:55:06 GMT",
          "content-encoding": "br",
          "cf-cache-status": "HIT",
          "age": "1935574",
          "cf-polished": "origSize=64047",
          "status": "200",
          "cf-request-id": "05213128450000feae0c956200000001",
          "last-modified": "Sun, 09 Aug 2020 21:22:22 GMT",
          "server": "cloudflare",
          "etag": "W/\"fa2f-5ac786f01df80\"",
          "expect-ct": "max-age=604800, report-uri=\"https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct\"",
          "vary": "Accept-Encoding,User-Agent",
          "content-type": "application/javascript",
          "expires": "Thu, 17 Sep 2020 13:38:56 GMT",
          "cache-control": "max-age=2592000",
          "content-security-policy": "default-src 'self' https://c.disquscdn.com https://disqus.com; script-src 'self' 'unsafe-inline' https://ssl.google-analytics.com https://api.github.com https://disqus.com https://go.disqus.com https://*.disquscdn.com https://www.google-analytics.com https://paulirish.disqus.com https://platform.twitter.com https://cdn.syndication.twimg.com; style-src 'self' 'unsafe-inline' https://fonts.googleapis.com https://platform.twitter.com; img-src * 'self' data:; font-src 'self' data: https://fonts.gstatic.com; connect-src 'self' https://firebaseinstallations.googleapis.com https://firebaselogging.googleapis.com  https://firebaseremoteconfig.googleapis.com https://www.google-analytics.com; media-src; object-src; prefetch-src *; child-src; frame-src 'self' https://platform.twitter.com https://accounts.google.com https://player.vimeo.com https://www.youtube.com https://apis.google.com https://disqus.com https://paulirish.wufoo.com;  upgrade-insecure-requests;report-uri https://paulirish.report-uri.com/r/d/csp/enforce;",
          "cf-ray": "5d155153abf0feae-IAH",
          "cf-bgj": "minify"
        },
        "mimeType": "application/javascript",
        "requestHeaders": {
          ":path": "/javascripts/firebase-performance.js",
          "sec-fetch-mode": "no-cors",
          "accept-encoding": "gzip, deflate, br",
          "accept-language": "en-US,en;q=0.9",
          "user-agent": "Mozilla/5.0 (Linux; Android 7.0; Moto G (4)) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4143.7 Mobile Safari/537.36 Chrome-Lighthouse",
          "accept": "*/*",
          "referer": "https://www.paulirish.com/",
          "sec-fetch-dest": "script",
          ":authority": "www.paulirish.com",
          "cookie": "_ga=GA1.2.1729210066.1594753805; __cfduid=d42e6b6800303a1fbd3cf7c0fe6b4f0fa1597940207; _gid=GA1.2.1000049010.1599865894; _gat=1",
          ":scheme": "https",
          "sec-fetch-site": "same-origin",
          ":method": "GET"
        },
        "connectionReused": true,
        "connectionId": 9012,
        "remoteIPAddress": "104.28.23.33",
        "remotePort": 443,
        "fromDiskCache": false,
        "fromServiceWorker": false,
        "fromPrefetchCache": false,
        "encodedDataLength": 20442,
        "timing": {
          "requestTime": 572120.888558,
          "proxyStart": 0.389,
          "proxyEnd": 0.635,
          "dnsStart": -1,
          "dnsEnd": -1,
          "connectStart": -1,
          "connectEnd": -1,
          "sslStart": -1,
          "sslEnd": -1,
          "workerStart": -1,
          "workerReady": -1,
          "workerFetchStart": -1,
          "workerRespondWithSettled": -1,
          "sendStart": 0.705,
          "sendEnd": 0.82,
          "pushStart": 0,
          "pushEnd": 0,
          "receiveHeadersEnd": 602.698
        },
        "responseTime": 1599868506191.166,
        "protocol": "h2",
        "securityState": "secure",
        "securityDetails": {
          "protocol": "TLS 1.3",
          "keyExchange": "",
          "keyExchangeGroup": "X25519",
          "cipher": "AES_128_GCM",
          "certificateId": 0,
          "subjectName": "sni.cloudflaressl.com",
          "sanList": [
            "paulirish.com",
            "sni.cloudflaressl.com",
            "*.paulirish.com"
          ],
          "issuer": "Cloudflare Inc ECC CA-3",
          "validFrom": 1595548800,
          "validTo": 1627128000,
          "signedCertificateTimestampList": [
            {
              "status": "Verified",
              "origin": "Embedded in certificate",
              "logDescription": "Google 'Argon2021' log",
              "logId": "F65C942FD1773022145418083094568EE34D131933BFDF0C2F200BCC4EF164E3",
              "timestamp": 1595567700006,
              "hashAlgorithm": "SHA-256",
              "signatureAlgorithm": "ECDSA",
              "signatureData": "304502201E5CE83AA7BAE618403970F57D84CA4A9C511EE06062322FB70F6CE12AC8832002210094815E1767254B1EA7DDD9AAB3618BF4F293315E744F1449B0D716B3E7A92848"
            },
            {
              "status": "Verified",
              "origin": "Embedded in certificate",
              "logDescription": "DigiCert Yeti2021 Log",
              "logId": "5CDC4392FEE6AB4544B15E9AD456E61037FBD5FA47DCA17394B25EE6F6C70ECA",
              "timestamp": 1595567700057,
              "hashAlgorithm": "SHA-256",
              "signatureAlgorithm": "ECDSA",
              "signatureData": "3045022100FC2DCFCFB1EC2C64EC36A6E75938B8C49AD124BD0CC96F16B334E8FE7C9CB6400220609D434E61CD7A92413709FB2038950F368541DCD1BAD4118BB80B0528E85724"
            }
          ],
          "certificateTransparencyCompliance": "compliant"
        }
      },
      "frameId": "596848B1492407A0F98476021D11CFA2"
    },
    "sessionId": "10028EC926C319C7F1E31B88D72B15AE"
  },
  {
    "method": "Network.dataReceived",
    "params": {
      "requestId": "20547.527",
      "timestamp": 572121.841561,
      "dataLength": 63390,
      "encodedDataLength": 0
    }
  },
  {
    "method": "Network.dataReceived",
    "params": {
      "requestId": "20547.527",
      "timestamp": 572121.841566,
      "dataLength": 63390,
      "encodedDataLength": 0
    },
    "sessionId": "10028EC926C319C7F1E31B88D72B15AE"
  },
  {
    "method": "Network.loadingFinished",
    "params": {
      "requestId": "20547.527",
      "timestamp": 572121.841437,
      "encodedDataLength": 20442,
      "shouldReportCorbBlocking": false
    }
  },
  {
    "method": "Network.loadingFinished",
    "params": {
      "requestId": "20547.527",
      "timestamp": 572121.841437,
      "encodedDataLength": 20442,
      "shouldReportCorbBlocking": false
    },
    "sessionId": "10028EC926C319C7F1E31B88D72B15AE"
  }
]

At least for the Network domain, we get two of each message ... one without a sessionId, and one with. No doubt this is related to the multi-client protocol work from awhile ago. Although I'm not 100% sure it's always been there, I'll do a bisect.

[connorjclark]

Bisect gave me: https://chromium.googlesource.com/chromium/src/+log/41ce21f10c765a426cc990c4714506ee4424347c..1079b28e253fa321c8d9379fed1e69b5b5c6fbbb

I wonder which one it is ;)

https://chromium.googlesource.com/chromium/src/+/1079b28e253fa321c8d9379fed1e69b5b5c6fbbb (I forgot about this).

[Lofesa]

Same here with images.
Affected Channels: DevTools
Lighthouse version: 6.4.0
Chrome version: Versión 88.0.4283.0 (Build oficial) canary (64 bits)