diff --git a/Source/SocketEngineSpec.swift b/Source/SocketEngineSpec.swift
index 785fc6f..2fde9f3 100644
--- a/Source/SocketEngineSpec.swift
+++ b/Source/SocketEngineSpec.swift
@@ -46,6 +46,7 @@ import Foundation
     var urlPolling: NSURL { get }
     var urlWebSocket: NSURL { get }
     var websocket: Bool { get }
+    optional var ws: WebSocket? { get }
     
     init(client: SocketEngineClient, url: NSURL, options: NSDictionary?)