How can I return binary data as part of a REST extension?

Hi,

I was trying to return binary data as part of a REST extension and am finding that even though the org.bonitasoft.web.extension.rest.RestApiResponseBuilder allows for a Serializable object as the response payload, the implementation appears to call toString() on the response object.
Placing binary data in a String subjects it to character encoding/corruption -- a Serialized object would have been perfect.

Looking at the https://github.com/bonitasoft/bonita-web-extensions/blob/master/src/main..., I have to provide a serializable.

Is it possible to send back my binary data as a serializable? How?
How can I return binary data as part of a REST extension?
How can I access the HttpServletResponse to send my binary data back?

Can you provide an example?

Thank you!