  void getReadBuffer(void** bufReturn, size_t* lenReturn) override {
    *bufReturn = buf_.get() + bytesRead_;
    *lenReturn = bufSize_ - bytesRead_;
  }
  void getReadBuffer(void** bufReturn, size_t* lenReturn) override {
    *bufReturn = buf_.get() + bytesRead_;
    *lenReturn = bufSize_ - bytesRead_;
  }