Macro flow_closure 

macro_rules! flow_closure {
    (|$world:ident $(: &mut $FlowWorld:ty)?| -> $ret:ty $code:block) => { ... };
    (|$world:ident $(: &mut $FlowWorld:ty)?| $code:expr) => { ... };
}

Converts closure syntax to flow fn.

There’s limitation that makes following |world: FlowWorld<'_>| async move { /*use world*/ } to be noncompilable.

On nightly it is possible to use async move |world: FlowWorld<'_>| { /*use world*/ } But this syntax is not stable yet and edict avoids requiring too many nighty features.

This macro is a workaround for this limitation.