This file adds a few custom methods to socket.io which provide the "built-in" websockets functionality for Sails.
Specifically, those methods allow you to send and receive Socket.IO messages to and from Sails by simulating a REST client interface on top of Socket.IO. It models its API after the $.ajax pattern from jQuery which you might be familiar with.
See the Socket client reference for more info about using the methods that this file provides.