In a hopeless attempt I've tried to use rawbodywriter, but then you can't inject stuff because you will run into problems with content-length (which I assume I'm not doing now )

I've written a little class that 'appends' a dynamic array after an inputstream (because I assumed writing a stream and then some text to bodywriter wouldn't work). Even that doesn't work. While my laptop claims it received all data from clientRequest, by the time it reaches my computer I get 'took to long to respond' or some sort.
When extending to https, I get the lovely informative "Handling of connection failed: Operating on closed TCPConnection." spammed a gazillion times in the terminal.

Am I missing something obvious? or is piping an outputstream through a inputstream broken?

At some point I even got the path to my libevent.a file spawned with a random string at the end. I think it's supposed to be a warning/error/exception?