docs: public MessageBufferOutput reset(MessageBufferOutput out)
              throws IOException
      {
          // Validate the argument
          MessageBufferOutput newOut = checkNotNull(out, "MessageBufferOutput is null");
  
          // Flush before reset
          flush();
          MessageBufferOutput old = this.out;
          this.out = newOut;
  
          // Reset totalFlushBytes
          this.totalFlushBytes = 0;
  
          return old;
      }