code: func (p *pullMediatorImpl) SendDigest(digest []string, nonce uint64, context interface{}) {
  	digMsg := &proto.GossipMessage{
  		Channel: p.config.Channel,
  		Tag:     p.config.Tag,
  		Nonce:   0,
  		Content: &proto.GossipMessage_DataDig{
  			DataDig: &proto.DataDigest{
  				MsgType: p.config.MsgType,
  				Nonce:   nonce,
  				Digests: util.StringsToBytes(digest),
  			},
  		},
  	}
  	remotePeer := context.(proto.ReceivedMessage).GetConnectionInfo()
  	if p.logger.IsEnabledFor(zapcore.DebugLevel) {
  		p.logger.Debug("Sending", p.config.MsgType, "digest:", digMsg.GetDataDig().FormattedDigests(), "to", remotePeer)
  	}
  
  	context.(proto.ReceivedMessage).Respond(digMsg)
  }
docs: // SendDigest sends a digest to a remote PullEngine.
  // The context parameter specifies the remote engine to send to.