Token.invalid with errno set.EventLoop.registerIdle
Register an idle watcher.
IDLE watchers fire once per loop iteration when no other events were dispatched (no I/O, timers, or signals fired). This happens regardless of what other watchers are registered — IDLE fires whenever the loop would otherwise be idle.
Use IDLE sparingly for lightweight background work. For periodic tasks, prefer registerTimer() with an appropriate interval.
Parameters
callback | Callback run when an iteration finishes with no dispatched work. |
Returns
New watcher token on success, or