code: func RegisterTLSConfig(key string, config *tls.Config) error {
  	tlsConfigLock.Lock()
  	if tlsConfigRegistry == nil {
  		tlsConfigRegistry = make(map[string]*tls.Config)
  	}
  
  	tlsConfigRegistry[key] = config
  	tlsConfigLock.Unlock()
  	return nil
  }
docs: // RegisterTLSConfig registers a custom tls.Config to be used with sql.Open.