start method

@override WorkFuture<D, T> start({ int retry = 0, OnProgress? onSendProgress, OnProgress? onReceiveProgress, })

启动任务

返回包含执行结果T的WorkFuture。

• retry为内部网络请求失败时的最大重试次数，0表示不重试，实际请求1次，1表示重试1次，实际最多请求两次，以此类推，
• onSendProgress为数据发送/上传进度监听器，在HttpMethod.get和HttpMethod.head中无效， 以及设置了WorkRequestOptions.downloadPath的下载任务中无效，
• onReceiveProgress为数据接收/下载进度监听器，
• 多次调用会启动多次请求

Implementation

@override
WorkFuture<D, T> start({
  int retry = 0,
  OnProgress? onSendProgress,
  OnProgress? onReceiveProgress,
}) {
  /// 日志标签
  final tag = '$runtimeType@${hashCode.toRadixString(16)}';

  log(tag, 'work start');

  void Function()? onCancel;

  final future = WorkFuture<D, T>._(tag, () => onCancel?.call());

  Future<void> onDo() async {
    int restart = 0;
    dynamic extra;
    T data;
    do {
      data = onCreateWorkData();
      data._restartCount = restart;
      data.extra = extra;
      onCancel = () => data.options?.cancelToken.cancel();
      if (!await _onDo(
        tag: tag,
        data: data,
        retry: retry,
        onSendProgress: onSendProgress,
        onReceiveProgress: onReceiveProgress,
      )) {
        break;
      }
      extra = data.extra;
    } while (restart++ < onMaxRestart());

    future._complete(data);
  }

  onDo();

  return future;
}