code: @Override
    protected void flush(Buffer data, boolean isEnd)
    {
      if (isClosed()) {
        throw new IllegalStateException();
      }
  
      _request.outProxy().write(_request, data, isEnd);
      
      /*
      boolean isHeader = ! isCommitted();
      toCommitted();
      
      MessageResponseHttp2 message;
      
      TempBuffer next = head;
      TempBuffer tBuf = null;
      
      if (head != null) {
        int headLength = head.length();
      
        if (headLength > 0) {
          tBuf = head;
        
          next = TempBuffer.allocate();
        }
      }
      
      message = new MessageResponseHttp2(_request, tBuf, isHeader, isEnd);
      _request.getOutHttp().offer(message);
      
      return next;
      */
    }
docs: Writes data to the output. If the headers have not been written,
  they should be written.