code: func (do *Domain) LogSlowQuery(query *SlowQueryInfo) {
  	do.slowQuery.mu.RLock()
  	defer do.slowQuery.mu.RUnlock()
  	if do.slowQuery.mu.closed {
  		return
  	}
  
  	select {
  	case do.slowQuery.ch <- query:
  	default:
  	}
  }
docs: // LogSlowQuery keeps topN recent slow queries in domain.