         return Singleton.instance
     }
 
-    var credentials:[Int:(String,String)]=[:]
     var taskConfigs:[TaskID:TaskConfiguration]=[:]
     var defaults:JustSessionDefaults!
     var session: NSURLSession!

}

typealias TaskID = Int
struct TaskConfiguration {
    var credential:(String, String)?
    var redirects:Bool
}


        json:[String:AnyObject]?,
        headers:[String:String],
        files:[String:HTTPFile],
        auth:Credentials?,
        cookies: [String:String],
        redirects:Bool,
        timeout:Double?,
