code: function consume (len) {
  		count -= len
  		if (count < 0) {
  			count = 0;
  			console.warn('Not enough samples fed for the next data frame. Expected frame is ' + samplesPerFrame + ' samples ' + channels + ' channels')
  		}
  
  		if (!callbackMarks.length) return
  
  		for (let i = 0, l = callbackMarks.length; i < l; i++) {
  			callbackMarks[i] = Math.max(callbackMarks[i] - len, 0)
  		}
  
  		while (callbackMarks[0] <= 0) {
  			callbackMarks.shift()
  			let cb = callbackQueue.shift()
  			cb()
  		}
  	}
docs: walk over callback stack, invoke according callbacks