If you have an IoT Hub and you send messages to a device you can have a FeedbackReceiver to request delivery acknowledgement, like described in : https://azure.microsoft.com/en-us/documentation/articles/iot-hub-csharp-csharp-c2d/#receiving-delivery-feedback
If you have multiple WorkerRole instances sending messages to a device how do you handle the feedbackReceiver.CompleteAsync()?
What if the feedbackBatch contains feedback from a message send by Instance 1 and also feedback from a message send by Instance 2? I tried to create a new feedbackBatch with only the records the specific instance has send and call CompleteAsync with this new batch, but then I get some Lock-Exception.