Remember to read the intro.
This circuit breaker will count the number of concurrent requests and will have an upper limit. Any request above that limit will fail immediately. Optionally this circuit breaker may decide to drain requests to a lower level once FAILING. For example we can allow 10 concurrent requests but if we ever go above that we fail all requests until less than 5 requests are pending.
This circuit breaker is great at protecting the resources of your service and will start failing quickly if there is a problem but also recover quickly. It may however suffer from a lot of false positives if the load is uneven with large peaks.