code: func (c *contextCache) GetEventService(channelID string, opts ...options.Opt) (fab.EventService, error) {
  	chnlCfg, err := c.GetChannelConfig(channelID)
  	if err != nil {
  		return nil, err
  	}
  	key, err := newEventCacheKey(chnlCfg, opts...)
  	if err != nil {
  		return nil, err
  	}
  	eventService, err := c.eventServiceCache.Get(key)
  	if err != nil {
  		return nil, err
  	}
  
  	return eventService.(fab.EventService), nil
  }
docs: // GetEventService returns the EventService.