+ /*
+ * Nests within the notification_client_list lock.
+ *
+ * Protects the outbound communication and the active flag which
+ * is used by both the notification and action executor threads.
+ *
+ * The remaining fields of the object can be used without any
+ * synchronization as they are either immutable (id, creds, version) or
+ * only accessed by the notification thread.
+ */