async fetchSegment_(request) {
    const type = shaka.net.NetworkingEngine.RequestType.SEGMENT;
    /** @type {!shaka.net.NetworkingEngine.PendingRequest} */
    const action = this.networkingEngine_.request(type, request);
    const abortCallback = () => {
      return action.abort();
    };
    this.abortCallbacks_.push(abortCallback);
    const response = await action.promise;
    shaka.util.ArrayUtils.remove(this.abortCallbacks_, abortCallback);
    return response.data;
  }
Download a segment and return the data in the response.

@param {shaka.extern.Request} request
@return {!Promise<BufferSource>}
@private