impl `JackHandler` for `FnMut + Send + 'static` about rust-jack HOT 4 CLOSED

 let x = 5;
 let x_ref = &x;
 let process_callback =
         ProcessClosure::new(move |ps: &jack::ProcessScope| -> jack::JackControl {
             // x_ref must still be valid here!
             let closure_x = *x_ref;
             out_a.data(ps).buffer().clone_from_slice(in_a.data(ps).buffer());
             out_b.data(ps).buffer().clone_from_slice(in_b.data(ps).buffer());
             jack::JackControl::Continue
         });
 // Activate the client, which starts the processing
 let active_client = client.activate(process_callback).unwrap();
 mem::forget(active_client);
 // Client is forgotten but not deregistered, stack pops up and x is lost
 // Callback then dereferences x_ref and gains access to stack garbage