Add(delta int) error

	// Done decrements the WaitGroup counter.
	Done()
}

// WithWaitGroup adds all non long-running requests to wait group, which is used for graceful shutdown.
func WithWaitGroup(handler http.Handler, longRunning apirequest.LongRunningRequestCheck, wg RequestWaitGroup) http.Handler {
	// NOTE: both WithWaitGroup and WithRetryAfter must use the same exact isRequestExemptFunc 'isRequestExemptFromRetryAfter,

//
// TODO: is there a way to merge WithWaitGroup and this filter?
func WithRetryAfter(handler http.Handler, shutdownDelayDurationElapsedCh <-chan struct{}) http.Handler {
	shutdownRetryAfterParams := &retryAfterParams{
		TearDownConnection: true,
		Message:            "The apiserver is shutting down, please try again later.",
	}

			if test.safeWaitGroupIsWaiting {
				// mark the safe wait group as waiting, it's a blocking call
				// but since the WaitGroup counter is zero it should not block
				safeWG.Wait()
			}

			wrapped := WithWaitGroup(handler, func(*http.Request, *apirequest.RequestInfo) bool {
				return false
			}, safeWG)
			wrapped = WithRetryAfter(wrapped, test.shutdownDelayDurationElapsedFn())