Macro thruster::async_middlewarez

macro_rules! async_middlewarez {
    (@internal $last:ident @internal_rest $head:ident, $($tail:ident),+) => { ... };
    (@internal $last:ident @internal_rest $head:ident) => { ... };
    (@return_type $ctx:ty) => { ... };
    ($outter_ctx:ty:$inner_ctx:ty, $($middlewares:ident),+) => { ... };
    ($ctx_type:ty, $($middlewares:ident),+) => { ... };
}