pub fn release_shared_session<N, C1, C2, A, B>(
    _n: N,
    cont: PartialSession<C2, B>
) -> PartialSession<C1, B> where
    A: Protocol,
    B: Protocol,
    C1: Context,
    C2: Context,
    A: SharedRecApp<SharedToLinear<LinearToShared<A>>>,
    N: ContextLens<C1, SharedToLinear<LinearToShared<A>>, Empty, Target = C2>,