create a mi

In [13]: mi = pd.MultiIndex.from_product([[1,2,3], list('abc'), pd.date_range('20200101', periods=2, tz='UTC')], names=['int', 'string', 'dt'])                            

You can already get .dtypes, but is slightly cumbersome. I would propose adding Multidex.dtypes (we already have MultiIndex.dtype but its always object). I think this is worth the convenience api.

OkDownload Version

1.0.5

Problem Describe

判断任务是否在运行的代码：

public synchronized boolean isRunning(DownloadTask task) {
        Util.d(TAG, "isRunning: " + task.getId());
        for (DownloadCall call : runningSyncCalls) {
            if (call.isCanceled()) continue;
            if (call.equalsTask(task)) {
                return true;
            }
        }