1. @override
Future<int> handle()

Handles the command input.

Override this method to perform actions for this command.

Return value is the value returned to the command line operation. Return 0 for success.

Source 

@override
Future<int> handle() async {
  try {
    var documentMap = await documentProject(projectDirectory.uri, libraryName);
    print("${JSON.encode(documentMap)}");
  } catch (e, st) {
    displayError("Failed to generate documentation");
    displayProgress("$e");
    if (showStacktrace) {
      displayProgress("$st");
    }

    return -1;
  }
  return 0;
}