resolve type of file and create stream from it

lib/Client.js

@@ -16,6 +16,7 @@ var PMChannel = require("./PMChannel.js");
 //node modules
 var request = require("superagent");
 var WebSocket = require("ws");
+var fs = require("fs");
 
 var defaultOptions = {
 	cache_tokens: false
@@ -535,7 +536,16 @@ var Client = (function () {
 
 			var self = this;
 
-			return new Promise(function (resolve, reject) {});
+			return new Promise(function (resolve, reject) {
+
+				var fstream;
+
+				if (typeof file === "string" || file instanceof String) {
+					fstream = fs.createReadStream(file);
+				} else {
+					fstream = file;
+				}
+			});
 		}
 	}, {
 		key: "sendMessage",