ServiceBusOutput puts entire message in body if returning ServiceBusMessage

[codebrane]

I need to return a message with application properties from ServiceBusOutput so can't just use a string return. If I return a ServiceBusMessage the Body contains the entire message and the original Body is lost.

Is there any way to return anything other than a string, byte[] or JSON from ServiceBusOutput as IAsyncCollector<ServiceBusMessage> is not available in isolated worker process.

[Function("TestTrigger")]
[ServiceBusOutput("%OutputQueueName%", Connection = "ServiceBusConnection", EntityType = ServiceBusEntityType.Queue)]
public IEnumerable Run(
    [ServiceBusTrigger(queueName: "%InputQueueName%", Connection = "ServiceBusConnection")] ServiceBusReceivedMessage message
{
    var outputMessage = new ServiceBusMessage
    {
        Body = message.Body,
        MessageId = message.MessageId
    };
    outputMessage.ApplicationProperties["TheRetryCount"] = "111";

    IEnumerable<ServiceBusMessage> outputMessages = new ServiceBusMessage[] { outputMessage };
    return outputMessages;
}

In ServiceBusExplorer the message body contains everything but the original body:

{
  "Body": {},
  "MessageId": "50cd3ad39d714367a339ceb28f2d7564",
  "PartitionKey": null,
  "TransactionPartitionKey": null,
  "SessionId": null,
  "ReplyToSessionId": null,
  "TimeToLive": "10675199.02:48:05.4775807",
  "CorrelationId": null,
  "Subject": null,
  "To": null,
  "ContentType": null,
  "ReplyTo": null,
  "ScheduledEnqueueTime": "0001-01-01T00:00:00+00:00",
  "ApplicationProperties": {
    "TheRetryCount": "111"
  }
}