This module implements the Apple Push Notification Service http://developer.apple.com/iPhone/library/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/Introduction/Introduction.html#//apple_ref/doc/uid/TP40008194-CH1-SW1

The notification service uses Chan for asynchronous communication. Call connectToNotificationService and pass it a NotificationCallbackChan. The notification service will post a NotificationServerConencted message, with a channel that you should use to send notifications with.