code: func (p *pullMediatorImpl) Remove(digest string) {
  	p.Lock()
  	defer p.Unlock()
  	delete(p.itemID2Msg, digest)
  	p.engine.Remove(digest)
  	p.logger.Debugf("Removed %s, total items: %d", digest, len(p.itemID2Msg))
  }
docs: // Remove removes a GossipMessage from the Mediator with a matching digest,
  // if such a message exits