streaming_strategy callback signature mismatch

[Gekctek]

Im having issues integrating with this library due to the fact that the callback signature for the streaming strategy has StreamingCallbackResponse as the return value vs ?StreamingCallbackResponse. The docs say its opt, but Im assuming this works due to candid null coercion
Normally I would just wrap it in another function, but its a shared function, so that wont work

[Gekctek]

Also ill have to figure out the StreamingToken type since that is app defined, but i want to keep mine generic. I have been using just Blob with from_candid

[tomijaga]

It should be StreamingCallbackResponse - The docs are a bit stale.

I started off serializing the StreamingToken using to_candid() initially but had some trouble testing. Now that the testing issues are resolved.
I think we can update the library to encode the StreamingToken to candid so it supports generic workflows.

I'm planning on updating the package this weekend. So the changes should be reflected then.