poll

type Poller interface {
	// Polls until "check" function returns "done=true".
	// If "check" returns a non-empty error, it logs and
	// continues the polling until context is canceled.
	// It returns the duration that it took to complete the check.
	Poll(
		ctx context.Context,
		check func() (done bool, err error),
	) (time.Duration, error)
}