A Key, Value mapping for metadata about the state of an AMPS connection.
Valid keys include:
client.uri The URI this client is connected to, NULL if no connection has been attempted.
client.name The name of this client.
client.username The most recently-used username for this client. NULL if no username is supplied.
publishStore.unpersistedCount The count of unpersisted messages in the local store. NULL if no PublishStore has been set on the client.
haClient.reconnectDelay The delay between reconnect attempts. NULL for non-HA clients.
haClient.timeout The default timeout used when re-logging on. NULL for non-HA clients.