code: func (c *Client) Hijack() io.ReadWriteCloser {
  	c.healthy = false
  	return c.conn
  }
docs: // Hijack exposes the underlying connection from this client.
  //
  // It also marks the connection as unhealthy since the client will
  // have lost control over the connection and can't otherwise verify
  // things are in good shape for connection pools.