+ *
+ * The @a mesh @a parameter can either be a valid MeshLink handle, or NULL.
+ * In case it is NULL, the callback will be called for errors that happen outside the context of a valid mesh instance.
+ * Otherwise, it will be called for errors that happen in the context of the given mesh instance.
+ *
+ * If @a mesh @a is not NULL, then the callback is run in MeshLink's own thread.