lua events without delay are executed instantly

Event.cpp

@@ -1855,6 +1855,10 @@ lua_event::export_as_text_( std::ostream &Output ) const {
     // nothing to do here
 }
 
+bool lua_event::is_instant() const {
+	return m_delay == 0.0 && m_delayrandom == 0.0;
+}
+
 // prepares event for use
 void
 message_event::init() {

Event.h

@@ -530,6 +530,7 @@ private:
     void deserialize_( cParser &Input, scene::scratch_data &Scratchpad ) override;
     void run_() override;
     void export_as_text_( std::ostream &Output ) const override;
+    bool is_instant() const override;
 
     lua::eventhandler_t lua_func = nullptr;
 };