abstract public function removeState($synckey);
/**
+ * Return the heartbeat interval, or zero if we have no existing state
+ *
+ * @param string $devId
+ *
+ * @return integer The hearbeat interval, or zero if not found.
+ * @throws Horde_ActiveSync_Exception
+ */
+ abstract public function getHeartbeatInterval();
+
+ abstract public function setHeartbeatInterval($lifetime);
+
+ /**
* Set the backend driver
* (should really only be called by a backend object when passing this
* object to client code)