Macro register_handlers 

macro_rules! register_handlers {
    ($svc:ident, $($req:ty => $rsp:ty => $handler:ty),+ $(,)?) => { ... };
}

👎Deprecated since 0.2.0:

HTTP handlers should use #[handler] / #[handler(inject)] (inventory). register_handlers! remains for non-HTTP Mediator scenarios only.