XML writer: flush after newlines
XML writer: flush after newlines

This is useful for hydra-eval-jobs.

zimbatm/nix,ttuegel/nix,ehmry/nix,shlevy/nix,zimbatm/nix,gebner/nix,dtzWill/nix,gebner/nix,jcumming/nix,dtzWill/nix,aucampia/nix,NixOS/nix,aucampia/nix,puffnfresh/nix,rycee/nix,nbp/nix,acowley/nix,bjornfor/nix,dezgeg/nix,rycee/nix,tchajed/nix,layus/nix,dtzWill/nix,aucampia/nix,joelmo/nix,pikajude/nix,bennofs/nix,bjornfor/nix,aucampia/nix,tchajed/nix,dezgeg/nix,offlinehacker/nix,joelmo/nix,offlinehacker/nix,pikajude/nix,vizanto/nix,ysangkok/nix,vizanto/nix,tchajed/nix,peti/nix,ehmry/nix,gridaphobe/nix,rowhit/nix,puffnfresh/nix,ttuegel/nix,jcumming/nix,ysangkok/nix,bennofs/nix,ehmry/nix,dtzWill/nix,pikajude/nix,ysangkok/nix,dezgeg/nix,gridaphobe/nix,vizanto/nix,dezgeg/nix,layus/nix,garbas/nix,edolstra/nix,jcumming/nix,vcunat/nix,vcunat/nix,nbp/nix,wmertens/nix,ttuegel/nix,shlevy/nix,ehmry/nix,bennofs/nix,edolstra/nix,gridaphobe/nix,joelmo/nix,zimbatm/nix,ttuegel/nix,garbas/nix,gebner/nix,nbp/nix,layus/nix,acowley/nix,vizanto/nix,nbp/nix,gridaphobe/nix,edolstra/nix,layus/nix,garbas/nix,rycee/nix,offlinehacker/nix,shlevy/nix,NixOS/nix,layus/nix,offlinehacker/nix,bjornfor/nix,ehmry/nix,wmertens/nix,NixOS/nix,peti/nix,zimbatm/nix,bennofs/nix,dezgeg/nix,acowley/nix,puffnfresh/nix,bjornfor/nix,puffnfresh/nix,wmertens/nix,ehmry/nix,edolstra/nix,dtzWill/nix,rycee/nix,NixOS/nix,shlevy/nix,edolstra/nix,joelmo/nix,peti/nix,NixOS/nix,vcunat/nix,rycee/nix,jcumming/nix,acowley/nix,tchajed/nix,wmertens/nix,garbas/nix,shlevy/nix,rowhit/nix,peti/nix,rowhit/nix,vcunat/nix,gebner/nix,rowhit/nix,garbas/nix,peti/nix