pub fn shared_forward<A1, A2, C>(
channel: SharedChannel<LinearToShared<A1>>,
) -> PartialSession<(Lock<A1>, C), SharedToLinear<LinearToShared<A1>>>where
A1: Protocol + SharedRecApp<SharedToLinear<LinearToShared<A1>>, Applied = A2>,
A2: Protocol,
C: EmptyContext,