Added comment to related method

cmd/conformance/mysql/main.go

@@ -207,6 +207,9 @@ func configureTilesReadAPI(mux *http.ServeMux, storage *mysql.Storage) {
 		}
 
 		// TODO: Add immutable Cache-Control header.
+		// Only do this once we're sure we're returning the right number of entries
+		// Currently a user can request a full tile and we can return a partial tile.
+		// If cache headers were set then this could cause caches to be poisoned.
 
 		if _, err := w.Write(entryBundle); err != nil {
 			klog.Errorf("/tile/entries/{index...}: %v", err)