code: func (s *ConfigService) FlushCache(cacheName string, input *CacheOperationInput) (*Response, error) {
  	u := fmt.Sprintf("config/server/caches/%s/flush", cacheName)
  
  	req, err := s.client.NewRequest("POST", u, input)
  	if err != nil {
  		return nil, err
  	}
  
  	return s.client.Do(req, nil)
  }
docs: // FlushCache flushes a cache.
  // The caller must be a member of a group that is granted one of the following capabilities:
  //
  // * Flush Caches (any cache except "web_sessions")
  // * Maintain Server (any cache including "web_sessions")
  // * Administrate Server (any cache including "web_sessions")
  //
  // Gerrit API docs: https://gerrit-review.googlesource.com/Documentation/rest-api-config.html#flush-cache