Can't seem to pipe to result stream from success callback:

module.exports = result => {
    foo().then(resp => resp.stream.pipe(result.stream);
}

Invoking the callback immediately like below works just fine.

module.exports = result => {
    foo().pipe(result.stream);
}

Works fine locally, when deployed to azure we get TaskCancellationException.

Example project to reproduce https://github.com/ajtowf/nodeservices/
Live example with full stacktrace https://nodeservices.azurewebsites.net/

Am I missing something obvious here?