static isBuffered(b, time) {
    if (!b || !b.length) {
      return false;
    }
    if (shaka.media.TimeRangesUtils.isBufferNegligible_(b)) {
      return false;
    }

    if (time > b.end(b.length - 1)) {
      return false;
    }

    return time >= b.start(0);
  }
Determines if the given time is inside a buffered range.

@param {TimeRanges} b
@param {number} time Playhead time
@return {boolean}