In Flutter I am using https://pub.dev/packages/record package to record audio.

AVAudioRecorder for iOS

I have used SystemChannels.lifecycle.setMessageHandler method to get Phone OS App Lifecycle state

When iPhone lock onPause called and I have user pause method to pause audio recording but when I unlock screen and call resume method it will only give recording before Lock Screen happened.

Example :

1. Record 4 sec audio and than lock device
2. Unlock device resume recording upto 10 sec
3. Stop Recording on 10 sec
4. It only gives 4 sec audio recorded file as source.

Same case working in Android.