#[derive(Clone)]
pub struct CompatClosure<C3, A, F3>(C3, PhantomData<A>, PhantomData<F3>) where
        F3: FutureExt,
        C3: FnOnce<A, Output = F3>;

impl<C3, A, F3> Fn<A> for CompatClosure<C3, A, F3> where
    F3: TryFuture + FutureExt + Send + 'static,
    Pin<Box<dyn Future<Output = <F3 as Future>::Output> + Send>>: TryFutureExt,
    C3: Fn<A, Output = F3> {

    extern "rust-call" fn call(&self, args: A) -> Self::Output {
        self.0.call(args).boxed().compat()
    }
}

impl<C3, A, F3> FnMut<A> for CompatClosure<C3, A, F3> where
    F3: TryFuture + FutureExt + Send + 'static,
    Pin<Box<dyn Future<Output = <F3 as Future>::Output> + Send>>: TryFutureExt,
    C3: FnMut<A, Output = F3> {

    extern "rust-call" fn call_mut(&mut self, args: A) -> Self::Output {
        self.0.call_mut(args).boxed().compat()
    }
}

impl<C3, A, F3> FnOnce<A> for CompatClosure<C3, A, F3> where
    F3: TryFuture + FutureExt + Send + 'static,
    Pin<Box<dyn Future<Output = <F3 as Future>::Output> + Send>>: TryFutureExt,
    C3: FnOnce<A, Output = F3> {

    type Output = compat::Compat<Pin<Box<dyn Future<Output = <F3 as Future>::Output> + Send>>>;

    extern "rust-call" fn call_once(self, args: A) -> Self::Output {
        self.0.call_once(args).boxed().compat()
    }
}


pub trait ClosureCompat<A, F3> where
         Self: Sized + FnOnce<A, Output = F3>,
         F3: TryFuture + FutureExt + Send + 'static {
    fn asdf(self) -> CompatClosure<Self, A, F3>;
}


impl<C3, A, F3> ClosureCompat<A, F3> for C3 where
        F3: TryFuture + FutureExt + Send + 'static,
        C3: FnOnce<A, Output = F3> + Sized {
    fn asdf(self) -> CompatClosure<Self, A, F3> {
        CompatClosure(self, PhantomData, PhantomData)
    }
}