Macro rat_event::flow

macro_rules! flow {
    ($x:expr) => { ... };
}

Breaks the control-flow if the result of the block implements ConsumedEvent and ConsumedEvent::is_consumed is true for the result.

It then does the classic into()-conversion and returns.

Special widget result-types are encourage to map down to Outcome as a baseline.

The difference to flow is that this one Ok-wraps the result.