Merge pull request #602 from mephi1984/patch-1

Update SocketEngine.swift

Author: nuclearace

Source/SocketEngine.swift

@@ -372,6 +372,7 @@ public final class SocketEngine : NSObject, URLSessionDelegate, SocketEnginePoll
 
         self.sid = sid
         connected = true
+        pongsMissed = 0
 
         if let upgrades = json["upgrades"] as? [String] {
             upgradeWs = upgrades.contains("websocket")