use async_recursion::async_recursion; #[async_recursion(?Send, Sync)] async fn not_send_sync_1() {} #[async_recursion(?Send,Sync)] async fn not_send_sync_2() {} #[async_recursion(Sync, ?Send)] async fn sync_not_send_1() {} #[async_recursion(Sync,?Send)] async fn sync_not_send_2() {}