Function test_pd::server::hijack_unary

fn hijack_unary<F, R, C: PdMocker>(
    mock: &mut PdMock<C>, 
    ctx: RpcContext<'_>, 
    sink: UnarySink<R>, 
    f: F
) where
    R: Send + 'static,
    F: Fn(&dyn PdMocker) -> Option<Result<R>>,