* Unbinds event handlers for either all of a non-instanced [Map]'s events, or one type of event. * * If `event_type` is `nil`, all the non-instanced [Map]'s event handlers are cleared. * * Otherwise, only event handlers for `event_type` are cleared. * * @proto (map_id) * @proto (map_id, event_type) * @param uint32 map_id : the ID of a [Map] * @param uin
source not stored for this graph (policy: none)