code: func (m *MockEventService) RegisterFilteredBlockEvent() (fab.Registration, <-chan *fab.FilteredBlockEvent, error) {
  	eventCh := make(chan *fab.FilteredBlockEvent)
  	reg := &dispatcher.FilteredBlockReg{
  		Eventch: eventCh,
  	}
  	return reg, eventCh, nil
  }
docs: // RegisterFilteredBlockEvent registers for filtered block events.