Flutter

Create a project from the command line:

flutter create my_app

will create a directory my_app in the current directory.

recording

https://github.com/Picovoice/flutter-voice-processor supports only Android and iOS. It is used in https://github.com/Picovoice/porcupine/tree/master/binding/flutter.

https://github.com/llfbandit/record/blob/master/record/pubspec.yaml is a good candidate since it supports many platforms. It uses https://github.com/flutter/packages/blob/main/packages/plugin_platform_interface/lib/plugin_platform_interface.dart to define an interface for different platforms.