A stalled HTTP response was canceled to prevent deadlock. This can happen when a Worker calls fetch() or cache.match() several times without reading the bodies of the returned Response objects. There is a limit on the number of concurrent HTTP requests that can be in-flight at one time. Normally, additional requests made beyond that limit are delayed until previous responses complete. However, because the Worker did not read the responses, they would never complete. Therefore, to prevent deadlock, the oldest response was canceled. To avoid this warning, make sure to either read the body of every HTTP Response or call response.body.cancel() to cancel a response that you don't plan to read from.