Msbuild: Document binarylogger as part of MSBuild 15.3 milestone

[ghuntley]

Heads up that https://docs.microsoft.com/en-us/visualstudio/msbuild/msbuild-command-line-reference will need to be updated when MSBuild 15.3 ships with insights from https://github.com/Microsoft/msbuild/wiki/Binary-Log

👍

[KirillOsenkov]

I've now created http://msbuildlog.com that is supposed to be a one-stop shop site about the binary log and the viewer. The site is open-source so please feel free to send PRs, open issues and suggest improvements :)

Also let me know if I can help in any way.

[ghuntley]

Freaking 💯 @KirillOsenkov. Nice work!

[KirillOsenkov]

The docs markdown on GitHub is kind of hard to write by hand, so here's what I came up with:

|/binaryLogger[:[LogFile=]`output.binlog`[;ProjectImports=[None,Embed,ZipFile]]]|/bl|Serializes all build events to a compressed binary file. By default the file is in the current directory and named `msbuild.binlog`. The binary log is a detailed description of the build process that can later be used to reconstruct text logs and used by other analysis tools. A binary log is usually 10-20x smaller than the most detailed text diagnostic-level log, but it contains more information.<br /><br />The binary logger by default collects the source text of project files, including all imported projects and target files encountered during the build. The optional ProjectImports switch controls this behavior:<br /><br /> -   **ProjectImports=None**. Don't collect the project imports.<br /> -   **ProjectImports=Embed**. Embed project imports in the log file (default).<br /> -   **ProjectImports=ZipFile**. Save project files to `output.projectimports.zip` where `output` is the same name as the binary log file name.<br /><br />The default setting for ProjectImports is Embed.<br />**Note**: the logger does not collect non-MSBuild source files such as `.cs`, `.cpp` etc.<br />A `.binlog` file can be "played back" by passing it to `msbuild.exe` as an argument instead of a project/solution. Other loggers will receive the information contained in the log file as if the original build was happening. You can read more about the binary log and its usages at: https://github.com/Microsoft/msbuild/wiki/Binary-Log <br />**Examples**:<br /> -   `/bl`<br /> -    `/bl:output.binlog`<br /> -   `/bl:output.binlog;ProjectImports=None`<br /> -   `/bl:output.binlog;ProjectImports=ZipFile`<br /> -   `/bl:..\..\custom.binlog`<br /> -   `/binaryLogger`|

[KirillOsenkov]

I've started a PR that adds the docs to the page:
https://github.com/MicrosoftDocs/visualstudio-docs/pull/216

[rainersigwald]

Docs PR went through.