The push data to use when forwarding the push payload to a device. The push data is equal to the data passed to [SINClient registerPushNotificationData:].

The push payload contains call information encoded by the Sinch SDK. The payload should considered opaque to the application developer, and should be delivered to the callee via appropriate push service, e.g. Apple Push Notification Service (APNS) or Google Cloud Messaging (GCM). Once received on the destination device, it should be passed to the Sinch SDK via the method [SINClient relayRemotePushNotificationPayload:].