docs: function(code, tracer, serverId, msg, opts, cb) {
  	let servers;
  	let self = this;
  	let counter = 0;
  	let success = true;
  	let serverType = msg.serverType;
  	if (!tracer || !tracer.servers) {
  		servers = self.serversMap[serverType];
  	} else {
  		servers = tracer.servers;
  	}
  
  	let index = servers.indexOf(serverId);
  	if (index >= 0) {
  		servers.splice(index, 1);
  	}
  	tracer && (tracer.servers = servers);
  
  	if (!servers.length) {
  		logger.error('[omelo-rpc] rpc failed with all this type of servers, with serverType: %s', serverType);
  		cb(new Error('rpc failed with all this type of servers, with serverType: ' + serverType));
  		return;
  	}
  	self.dispatch.call(self, tracer, servers[0], msg, opts, cb);
  }