Classes
| GcmListenerService | Base class for communicating with Google Cloud Messaging. |
| GcmNetworkManager | Class to create apps with robust "send-to-sync", which is the mechanism to sync data with servers where new information is available. |
| GcmPubSub | GcmPubSub provides a publish-subscribe model for sending GCM topic messages. |
| GcmReceiver | WakefulBroadcastReceiver that receives GCM messages and delivers them to an
application-specific GcmListenerService subclass. |
| GcmTaskService | Implemented by the client application to provide an endpoint for the GcmNetworkManager
to call back to when a task is ready to be executed. |
| GoogleCloudMessaging | Google Cloud Messaging (GCM) is now part of Firebase and has been rebranded as Firebase Cloud Messaging (FCM). |
| OneoffTask | A task that will execute once,at some point within the specified window. |
| OneoffTask.Builder | |
| PeriodicTask | A periodic task is one that will recur at the specified interval, without needing to be rescheduled. |
| PeriodicTask.Builder | |
| Task | Encapsulates the parameters of a task that you will schedule on the
GcmNetworkManager. |
| Task.Builder | Builder object to construct these tasks before sending them to the network manager. |
| TaskParams | Container of parameters handed off to the client app in
onRunTask(TaskParams). |