This is a tracking ticket to prioritize adding introspection into more layers of the service discovery pipeline:

• Modify klog to be verbose when controller log-level is set to debug #2221 API responses from k8s api server
• k8s client cache
• informer cache
• Introduce Discovery API and endpoints command #2195 endpoints watcher cache
• API messages to proxy
• proxy internal state

Based on #2195 (comment)