_pump(controller, reader, uint8Array) {
    return reader.read().then(({ value, done }) => {
      if (done) {
        return uint8Array;
      }

      const newArray = new Uint8Array(uint8Array.length + value.length);
      newArray.set(uint8Array);
      newArray.set(value, uint8Array.length);
      return this._pump(controller, reader, newArray);
    }).catch((err) => console.error(err));
  }
@param {ReadableStreamDefaultController} controller
@param {ReadableStreamDefaultReader} reader
@param {Uint8Array} uint8Array