Enum JoinResult 

pub(crate) enum JoinResult<'a, Key, Val, We, B, L> {
    Filled(Option<Arc<Placeholder<Val>>>),
    Guard(PlaceholderGuard<'a, Key, Val, We, B, L>),
    Timeout,
}

Result of waiting for a placeholder or JoinFuture.

Variants

Filled(Option<Arc<Placeholder<Val>>>)

Value is available — either found directly in the cache (None) or inside the shared placeholder (Some).

Guard(PlaceholderGuard<'a, Key, Val, We, B, L>)

Got the guard — caller should load the value.

Timeout

Timed out waiting (sync paths only).