code: func (c *ConnReq) String() string {
  	if c.Addr == nil || c.Addr.String() == "" {
  		return fmt.Sprintf("reqid %d", atomic.LoadUint64(&c.id))
  	}
  	return fmt.Sprintf("%s (reqid %d)", c.Addr, atomic.LoadUint64(&c.id))
  }
docs: // String returns a human-readable string for the connection request.