Function apply_state 

fn apply_state<R: Runtime>(
    dirmgr: &Arc<DirMgr<R>>,
    state: &mut Box<dyn DirState>,
    attempt_id: AttemptId,
) -> Result<()>

Applies changes from state to the manager’s netdir.

Updates and broadcasts download progress based on the current state. Panics if manager’s store lock is poisoned.