Macro run_with_obs_impl 

macro_rules! run_with_obs_impl {
    ($runtime:expr, $operation:expr) => { ... };
    ($runtime:expr, ($($var:ident),* $(,)*), $operation:expr) => { ... };
    (SEPARATE_THREAD, $runtime:expr, ($($var:ident),* $(,)*), $operation:expr) => { ... };
}