Cli: Reload/open dev menu commands don't work reliably (watch mode)

[lucasbento]

Environment

System:
    OS: macOS 10.15.2
    CPU: (8) x64 Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz
    Memory: 101.23 MB / 16.00 GB
    Shell: 5.7.1 - /bin/zsh
  Binaries:
    Node: 13.8.0 - /usr/local/bin/node
    Yarn: 1.22.0 - /usr/local/bin/yarn
    npm: 6.13.7 - /usr/local/bin/npm
    Watchman: 4.9.0 - /usr/local/bin/watchman
  SDKs:
    iOS SDK:
      Platforms: iOS 13.2, DriverKit 19.0, macOS 10.15, tvOS 13.2, watchOS 6.1
    Android SDK:
      API Levels: 28, 29
      Build Tools: 28.0.3, 29.0.2
      System Images: android-27 | Google APIs Intel x86 Atom, android-27 | Google Play Intel x86 Atom
  IDEs:
    Android Studio: 3.5 AI-191.8026.42.35.6010548
    Xcode: 11.3.1/11C505 - /usr/bin/xcodebuild
  npmPackages:
    react: 16.11.0 => 16.11.0 
    react-native: 0.62.0-rc.2 => 0.62.0-rc.2 
  npmGlobalPackages:
    react-native-cli: 2.0.1

Description

Currently reloading or opening the developer menu using the watch mode don't work reliably, in the simulator only the reload works, for iOS physical devices none of them work.

This is reproducible with react-native on versions 0.61.5 and 0.62.0-rc.2.

It also affects the /reload endpoint added in #574 and the Flipper events added in #953.

Reproducible Demo

1. Run react-native init CoolApp --version 0.62.0-rc.2;
2. Run the app;
3. Try to reload or open the developer menu.

[thymikee]

cc @TheSavior who worked on https://github.com/react-native-community/cli/pull/574. Maybe more of a Metro issue?

[TheSavior]

I defer to @rickhanlonii here

[grabbou]

Not sure this is CLI issue, but an underlying React Native? AFAIK the proxy works just fine - the events are being broadcasted. I guess we should figure out where is the root cause of the problem - whether it happens on the CLI side or not.