Pending   The message has been sent but not received.

Receiving   The message is in the process of being received, or it was received but not acknowledged.

Final   The message has achieved a final state.

Expired   The message was not received before its expiration time has passed.

Cancelled   The message has been cancelled.

Unreceivable   The message is either malformed, or there were too many failed attempts to deliver it.

Received   The message has been received and acknowledged.