Log a Warning if messages are deleted from the StoreAndForward/offline cache (because of TTL)
Currently there is no way to figure out that messages were deleted because of the Time To Live/TTL StoreAndForward configuration. There should be a warning in the Logs if this happens to hint the deletion of messages that were not sent to IoT Hub. Ideally there is a configurable second warning before this happens (e.g. 10 minutes before messages get deleted because of TTL).
In addition it would be great to add more control to the StoreAndForward/Caching/Queuing functionality of messaging - refer to ideas https://feedback.azure.com/forums/907045-azure-iot-edge/suggestions/33534802-more-options-or-configuration-parameters-of-stor and https://feedback.azure.com/forums/907045-azure-iot-edge/suggestions/36632884-low-bandwidth-partially-connected-message-deliv
We are currently adding the ability to pull metrics from the runtime so that customers can understand how their Edge devices are performing in the field. Message drops due to TTL is one of the metrics we’ll be exposing. I do not expect this feature for a few months, likely 1.0.10.