update player_id in sent-out SetState messages

src/net/server.rs

@@ -115,9 +115,10 @@ impl Server {
         // remove_player(&mut self) in the error case
         for slot in 0..self.players.len() {
             if let Some(ref mut player) = self.players[slot] {
+                let msg_for_player = Server::postprocess_message(slot, &msg);
                 // don't poll ready; we give the channel enough buffer that an overflow indicates
                 // the client has fallen hopelessly behind.
-                if player.sender.start_send(msg.clone()).is_err() {
+                if player.sender.start_send(msg_for_player).is_err() {
                     info!("Client#{} fell behind", slot);
                     self.remove_player(slot);
                 }
@@ -125,6 +126,21 @@ impl Server {
         }
     }
 
+    /// given a reference to a ServerMessage, do any per-player "customization" that
+    // may be called for, returning an owned instance
+    fn postprocess_message(player: PlayerId, msg: &ServerMessage) -> ServerMessage {
+        match msg {
+            ServerMessage::SetState {
+                player_id: _,
+                state,
+            } => ServerMessage::SetState {
+                player_id: Some(player),
+                state: state.clone(),
+            },
+            msg => msg.clone(),
+        }
+    }
+
     pub fn remove_player(&mut self, player_id: PlayerId) {
         if player_id < self.players.len() && self.players[player_id].is_some() {
             self.players[player_id] = None;