Is there an API to inspect a task queue's backlog from within app engine flex? App Engine Standard has the com.google.appengine.api.taskqueue.Queue.fetchStatistics API but that seems to fail in App Engine Flex with error: com.google.apphosting.api.ApiProxy$CallNotFoundException: Can't make API call taskqueue.FetchQueueStats in a thread that is neither the original request thread nor a thread created by ThreadManager
The Task Queue API was deprecated and is currently only available for App Engine Standard 1st generation runtime.
For App Engine Flex, Standard 2nd gen and other applications, you should use the Cloud Tasks API