code: func (eca *ExternalCA) UpdateTLSConfig(tlsConfig *tls.Config) {
  	eca.mu.Lock()
  	defer eca.mu.Unlock()
  
  	eca.client = &http.Client{
  		Transport: &http.Transport{
  			TLSClientConfig: tlsConfig,
  		},
  	}
  }
docs: // UpdateTLSConfig updates the HTTP Client for this ExternalCA by creating
  // a new client which uses the given tlsConfig.