code: func (c *Connection) TxTimedOut() bool {
  	c.timeMu.Lock()
  	defer c.timeMu.Unlock()
  	c.txStateMu.Lock()
  	defer c.txStateMu.Unlock()
  	lau := c.LastUsedAt
  	return !c.TxStartedAt.IsZero() && time.Since(lau) > c.TxTimeout && c.TxTimeout != 0
  }
docs: // TxTimedOut returns if the transaction has been open, without activity in
  // transaction-idle time.