@Override
            public CompletableFuture<Endpoint> select(ClientRequestContext ctx,
                                                      ScheduledExecutorService executor,
                                                      long timeoutMillis) {
                if (selectCounter.decrementAndGet() <= 0) {
                    return selectBehavior.apply(ctx);
                }
                return delegate.select(ctx, executor, timeoutMillis);
            }
Counts down a user provided counter each time an endpoint is selected asynchronously.
Once the countdown is complete, the user defined behavior is executed.
testing-internal/src/main/java/com/linecorp/armeria/internal/testing/CountDownEmptyEndpointStrategy.java