[Error]The AudioContext was not allowed to start. It must be resumed (or created) after a user gesture on the page.

问题：
chrome使用AudioContext时有时会遇到，用户点击了microphone button同时也允许麦克风打开，但无法获取到audio input，相同代码在edge上可以正常运行。console有以下warning：

The AudioContext was not allowed to start. It must be resumed (or created) after a user gesture on the page.

解决：
warining中已提示，在获取到user gesture后resume or created。

    navigator.mediaDevices.getUserMedia(mediaConstraints).then(stream => {
      context.resume().then(() => {
            //do your job with microphone input
      });
    });