+/// A callback reporting node path MTU changes.
+/** @param mesh A handle which represents an instance of MeshLink.
+ * @param node A pointer to a meshlink_node_t describing the node whose status changed.
+ * This pointer is valid until meshlink_close() is called.
+ * @param pmtu The current path MTU to the node, or 0 if UDP communication is not (yet) possible.
+ */
+typedef void (*node_pmtu_cb_t)(mesh *mesh, node *node, uint16_t pmtu);
+