onDone method
Implementation
void onDone(Object? error, Object? result) {
if (cancelled || done) return;
_done = true;
_error = error;
if (error == null) {
_result = result;
_successEmitter.emit(null);
} else {
// set last error
cubix._error = error;
_errorEmitter.emit(error);
}
_doneEmitter.emit(null);
}