Upgrade tokio to 1.10 (#9575)

* Upgrade tokio to 1.10

* Fix test runner

* Try fix it

* Update Cargo.lock

* Review feedback

* ahhhh

* FML

* FMT

* Fix tests

substrate/client/service/src/task_manager/mod.rs

@@ -311,7 +311,13 @@ impl TaskManager {
 		Box::pin(async move {
 			join_all(children_shutdowns).await;
 			completion_future.await;
-			drop(keep_alive);
+
+			// The keep_alive stuff is holding references to some RPC handles etc. These
+			// RPC handles spawn their own tokio stuff and that doesn't like to be closed in an
+			// async context. So, we move the deletion to some other thread.
+			std::thread::spawn(move || {
+				let _ = keep_alive;
+			});
 		})
 	}