A lean and fast proxy designed to be a sidecar to deduplicate concurrent HTTP GET requests targeting the same endpoints. As a result, there will be at most 1 actual outstanding request against the same GET endpoint to the backend. Deduplicated requests in front of this proxy will then share the same response.

The primary use case is to batch concurrent Prometheus scraping requests and Kubernetes kubelet liveness/readiness probe requests targeting a container's /metrics endpoint. For some applications, it might be very expensive to construct and render /metrics if it's processed on-demand and with lots of IOs involved. This cost is then amplified when multiple Prometheus servers concurrently scrape together with kubelet hammering the same endpoint with probe requests.