In continuation #380.
Add server buffered write on plan/ssl connections.
Also add check for result returned by flush nextstrm in compressed streams (due to write buffered now).
Add some tests. Also add install zlib headers on Linux.
On MacOS don't do it, gzip tests don run.
In continuation #380. Add server buffered write on plan/ssl connections. Also add check for result returned by flush nextstrm in compressed streams (due to write buffered now). Add some tests. Also add install zlib headers on Linux. On MacOS don't do it, gzip tests don run.