Macro relm::connect_async_full

macro_rules! connect_async_full {
    ($object:expr, $async_method:ident, $relm:expr, $msg:expr) => { ... };
    ($object:expr, $async_method:ident ( $($args:expr),* ), $relm:expr, $msg:expr) => { ... };
    ($object:expr, $async_method:ident, $relm:expr, $msg:expr, $fail_msg:expr) => { ... };
    ($object:expr, $async_method:ident ( $($args:expr),* ), $relm:expr, $msg:expr, $fail_msg:expr) => { ... };
}

Like connect_async!, but also return a Cancellable to control the asynchronous request.