Function staticCompositionLocalOfWithPolicy 

pub fn staticCompositionLocalOfWithPolicy<T: Clone + 'static>(
    default: impl Fn() -> T + 'static,
    equivalent: impl Fn(&T, &T) -> bool + Send + Sync + 'static,
) -> StaticCompositionLocal<T>

A StaticCompositionLocal whose provider recomposes its content when equivalent says a new value differs from the last one.