add arc mutex to generics 3

ext/net/ops.rs

@@ -873,7 +873,7 @@ mod tests {
  });
  let my_ext = Extension::builder()
  .state(move |state| {
- state.put(TestPermission {});
+ state.put(Arc::new(Mutex::new(TestPermission {})));
  state.put(UnstableChecker { unstable: true });
  Ok(())
  })