Gets the collapse key used for collapsible messages.

Gets or sets the metadata, including all original key/value pairs.

Includes some of the HTTP headers used when sending the message.gcm,google andgoog prefixes are reserved for internal use.

Gets the error code.

Used in "nack" messages for CCS, and in responses from the server. See the CCS specification for the externally-supported list.

Gets the human readable details about the error.

Gets the authenticated ID of the sender. This is a project number in most cases.

The link into the app from the message.

Gets or sets the message ID.

This can be specified by sender. Internally a hash of the message ID and other elements will be used for storage. The ID must be unique for each topic subscription - using the same ID may result in overriding the original message or duplicate delivery.

Gets the message type, equivalent with a content-type.

CCS uses "ack", "nack" for flow control and error handling. "control" is used by CCS for connection control.

Optional notification to show.

This only set if a notification was received with this message, otherwise it is null.

Gets a flag indicating whether this message was opened by tapping a notification in the OS system tray.

If the message was received this way this flag is set to true.

Gets the priority level.

Defined values are "normal" and "high". By default messages are sent with normal priority.

Gets the binary payload.

For webpush and non-json messages, this is the body of the request entity.

The Time To Live (TTL) for the message.

Gets or sets recipient of a message.

For example it can be a registration token, a topic name, a IID or project ID.