proto: add remote

other/java/client/src/main/proto/filer.proto

@@ -101,6 +101,13 @@ message Entry {
     bytes hard_link_id = 7;
     int32 hard_link_counter = 8; // only exists in hard link meta data
     bytes content = 9; // if not empty, the file content
+
+    message Remote {
+        int64 last_modified_at = 1;
+        int64 size = 2;
+        string e_tag = 3;
+    }
+    Remote remote = 10;
 }
 
 message FullEntry {