echoCancel doesn't work on Android

[jaween]

Package version
5.1.1

Environment

• OS: Android13

Describe the bug
On Android with echoCancel enabled, the currently playing audio is still packed up in the recording stream, when it should not. This works on iOS, but not Android even though the pub.dev listing says it does work on Android. Here is the RecordConfig:

final stream = await _recorder.startStream(
  RecordConfig(
    encoder: AudioEncoder.pcm16bits,
    echoCancel: true,
  ),
);

Expected behavior
With echoCancel enabled, the currently playing audio should not be picked up in the recording stream.

Additional context
My use case is a voip app, the user needs to be able to hear the other person's audio, but the other person should not hear their own audio.

[jaween]

Without using using echoCancel on the Flutter side, I tried changing the AudioSource on the Android side from DEFAULT to VOICE_COMMUNICATION and it does seem to successfully enable echo cancelation:

record/record_android/android/src/main/kotlin/com/llfbandit/record/record/PCMReader.kt

Lines 95 to 102 in d8b6812

	val reader = try {
	AudioRecord(
	MediaRecorder.AudioSource.DEFAULT,
	sampleRate,
	channels,
	audioFormat,
	bufferSize
	)

So maybe the issue is that AudioSource.DEFAULT don't support certain AudioEffects such as the AcousticEchoCanceler?