increase command flexibility

flight/src/scheduler/mod.rs

@@ -51,8 +51,7 @@ where
     type Message = ();
     type Data = ();
 
-    fn get_data(&self) -> Self::Data {
-    }
+    fn get_data(&self) -> Self::Data {}
 
     fn step(&mut self, _receiver: &Receiver<Self::Message>, _step_time: Instant) {
         self();