a bit cleaner, in send_message_to_device in TunnelbrokerService below, example how to use it

You're changes were changing the error response here, try this - you can follow the same pattern in TokenConnection to use conversion to TokenConnectionError

This is not really correct, you are wrapping all errors into one MessageParsingFailed (even those caused by DDB or AMQP), try something better for debugging this in the future:

1. Adding one general error like QueueingMessageToDeviceFailed and using it here, but replace Box with SendMessageError
2. Use more detailed errors in TokenConnectionError and use conversion like in my comment above

Swallowing error here is fine, I guess, but I would emit metrics for this to be aware of why this is happening and how often. You can use metricType = "TokenDistributor_ConnectionFailure" (examples in this file)

This is a bad idea; it is better to handle this and return TokenConnectionError

This error is always converted to MessageParsingFailed which is not great, I already suggested how to fix it above

One additional note: I don't think wrapping this in one error is bad, but the name of this error here is misguided