code: func (c *RPCClient) SyncStreams(stdout io.Writer, stderr io.Writer) error {
  	go copyStream("stdout", stdout, c.stdout)
  	go copyStream("stderr", stderr, c.stderr)
  	return nil
  }
docs: // SyncStreams should be called to enable syncing of stdout,
  // stderr with the plugin.
  //
  // This will return immediately and the syncing will continue to happen
  // in the background. You do not need to launch this in a goroutine itself.
  //
  // This should never be called multiple times.