Add #[rtype(...)] to sec-3 example.
@@ -83,10 +83,12 @@ be any actor that implements the `Handler<Signal>` trait.
# #[macro_use] extern crate actix;
# use actix::prelude::*;
#[derive(Message)]
+#[rtype(result = "()")]
struct Signal(usize);
/// Subscribe to process signals.
#[derive(Message)]
+#[rtype(result = "()")]
struct Subscribe(pub Recipient<Signal>);
/// Actor that provides signal subscriptions
