Add response and compacting function to HtmlResponseHandler
Add response and compacting function to HtmlResponseHandler

The encode() function has such a shitty signature because of flate2's
shitty design: each encoder is a separate type with the same name,
exported with a different one, so we can't call compressor.finish()
directly, so we delegate it to a user-provided function.

Ref: #1

nabijaczleweli/chattium-oxide-server,nabijaczleweli/chattium-oxide-server,nabijaczleweli/chattium-oxide-server