Macro osaka::sync

macro_rules! sync {
    ($task:expr) => { ... };
}

convenience macro to wait for another future inside an osaka async fn

if bar is a future that returns a string, for example:

let foo : String = sync!(bar);
printfn!("yo! {}", foo);

this is asynchronous and does not block the current thread. Instead it will return the Again activation handle of bar if its not ready