From flutter run -v I get the following:

<- compile package:foo/main.dart
[...]
<- reset
<- recompile package:foo/main.dart 995dae5c-e4e5-4515-b1ab-8e81d2f7c950

Digging in to this a bit it:

• Compiles (possibly by initializing from dill) here:

  flutter/packages/flutter_tools/lib/src/run_hot.dart

  Line 376 in 93da78f

  device.generator.recompile(

• Waits for the compile (and other stuff) to finish here:

  flutter/packages/flutter_tools/lib/src/run_hot.dart

  Line 422 in 93da78f

  final List<bool> results = await Future.wait(startupTasks);

• Then calls attach here:

  flutter/packages/flutter_tools/lib/src/run_hot.dart

  Line 434 in 93da78f

  return attach(

  --- which
• compiles again here:

  flutter/packages/flutter_tools/lib/src/run_hot.dart

  Line 278 in 93da78f

  final UpdateFSReport devfsResult = await _updateDevFS(fullRestart: true);

  with a so called full restart --- having the effect of compiling again (e.g. serializing the full (and thus rather big dill file) again) and not sending it to the device (here:

  flutter/packages/flutter_tools/lib/src/devfs.dart

  Lines 652 to 660 in 93da78f

  	if (!bundleFirstUpload) {
  	final String compiledBinary = compilerOutput.outputFilename;
  	if (compiledBinary.isNotEmpty) {
  	final Uri entryUri = _fileSystem.path.toUri(pathToReload);
  	final DevFSFileContent content = DevFSFileContent(_fileSystem.file(compiledBinary));
  	syncedBytes += content.size;
  	dirtyEntries[entryUri] = content;
  	}
  	}

  ).

I don't understand why we do this. For context this - on my machine - adds 1100+ ms to the startup for big apps.
Is there a good reason for doing this, and if not could we not do it? (and if there is could we potentially tweak it a bit?)

/cc @christopherfujino (which I've been told should in many ways be our point of contact).
/cc @aam which seemingly added the "don't send over the dill" stuff 3 years ago in #21133
/cc @chingjun which will be interested in skipping this for big apps too.