handle method
Implementation
@override
FutureOr<BuildTransaction> handle(BuildTransaction data) async {
final dartDefineString = data.env.map((e) => e.dartDefine).join(' ');
final cmdBuffer = StringBuffer()
..write('build ${data.settings.platform.name} ')
..write('--${data.settings.type.name} $dartDefineString');
final args = cmdBuffer.toString().trim();
final controller = ShellLinesController();
final shell = Shell(
workingDirectory: data.settings.directory.path,
stdout: controller.sink,
);
final cmd = '${data.settings.flutterExecutable} $args';
await shell.run(cmd);
shell.kill(ProcessSignal.sigquit);
return data;
}