Macro wrap_life_span_handler 

macro_rules! wrap_life_span_handler {
    ($ vis : vis struct $ name : ident ; impl LifeSpanHandler { $ ($ (# [$ attrs_name : meta]) * fn $ method_name : ident (& $ self : ident $ (, $ arg_name : ident : $ arg_type : ty) * $ (,) ?) $ (-> $ return_type : ty) ? { $ ($ body : tt) * }) * }) => { ... };
    ($ vis : vis struct $ name : ident $ (< $ ($ generic_type : ident : $ first_generic_type_bound : tt $ (+ $ generic_type_bound : tt) *) , + $ (,) ? >) ? { $ ($ field_vis : vis $ field_name : ident : $ field_type : ty) , * $ (,) ? } impl LifeSpanHandler { $ ($ (# [$ attrs_name : meta]) * fn $ method_name : ident (& $ self : ident $ (, $ arg_name : ident : $ arg_type : ty) * $ (,) ?) $ (-> $ return_type : ty) ? { $ ($ body : tt) * }) * }) => { ... };
}

Implement the WrapLifeSpanHandler trait for the specified struct. You can declare more members for your struct, and in the impl LifeSpanHandler block you can override default methods implemented by the ImplLifeSpanHandler trait.

Example

wrap_life_span_handler! {
    struct MyLifeSpanHandler {
        payload: String,
    }

    impl LifeSpanHandler {
        // ...
    }
}

fn make_my_struct() -> LifeSpanHandler {
    MyLifeSpanHandler::new("payload".to_string())
}