Using Dispatch Internals for Testing

[sveinhal (Svein Halvor Halvorsen)]

@SlaunchaMan

func currentQueueName() -> String? { 
    let name = __dispatch_queue_get_label(nil) 
    return String(cString: name, encoding: .utf8) 
}

I've resorted to the same trick in my tests: Dispatch precondition false positive?