record(sFile, duration, callback) {
    this._workletNode.port.postMessage({ name: 'start', duration: duration });

    if (sFile && callback) {
      this._callback = function (buffer) {
        sFile.setBuffer(buffer);
        callback();
      };
    } else if (sFile) {
      this._callback = function (buffer) {
        sFile.setBuffer(buffer);
      };
    }
  }
Start recording. To access the recording, provide
 a p5.SoundFile as the first parameter. The p5.SoundRecorder
 will send its recording to that p5.SoundFile for playback once
 recording is complete. Optional parameters include duration
 (in seconds) of the recording, and a callback function that
 will be called once the complete recording has been
 transfered to the p5.SoundFile.

 @method  record
 @for p5.SoundRecorder
 @param  {p5.SoundFile}   soundFile    p5.SoundFile
 @param  {Number}   [duration] Time (in seconds)
 @param  {Function} [callback] The name of a function that will be
                               called once the recording completes