Image/Media MIME type responses in Undertow

I've been struggling trying to find a way to deliver .jpeg, .png or other contents in Undertow. Sending byte[] won't work and since Undertow is Non-blocking, I don't want to write the file on the output by doing the usual:

exchange.getOutputStream().write(myFileByteArray);

Is there any other way I can achieve it? I also encoded the image in Base64 using Undertow's default Base64 library, but didn't work either.

Thanks.