Replace the one-thread-per-timeout model by a two-thread model of timeouts.
Replace the one-thread-per-timeout model by a two-thread model of timeouts.

anthgur/servo,mbrubeck/servo,DominoTree/servo,anthgur/servo,anthgur/servo,peterjoel/servo,mbrubeck/servo,emilio/servo,mattnenterprise/servo,avadacatavra/servo,sadmansk/servo,rnestler/servo,dsandeephegde/servo,mattnenterprise/servo,KiChjang/servo,emilio/servo,emilio/servo,dati91/servo,pyfisch/servo,jimberlage/servo,eddyb/servo,upsuper/servo,fiji-flo/servo,emilio/servo,larsbergstrom/servo,sadmansk/servo,nrc/servo,upsuper/servo,thiagopnts/servo,mbrubeck/servo,KiChjang/servo,nrc/servo,dati91/servo,DominoTree/servo,splav/servo,jimberlage/servo,KiChjang/servo,sadmansk/servo,larsbergstrom/servo,szeged/servo,emilio/servo,mattnenterprise/servo,fiji-flo/servo,nrc/servo,dsandeephegde/servo,ConnorGBrewster/servo,splav/servo,SimonSapin/servo,larsbergstrom/servo,splav/servo,nrc/servo,nnethercote/servo,KiChjang/servo,paulrouget/servo,paulrouget/servo,sadmansk/servo,avadacatavra/servo,avadacatavra/servo,splav/servo,szeged/servo,nnethercote/servo,eddyb/servo,CJ8664/servo,upsuper/servo,dsandeephegde/servo,emilio/servo,pyfisch/servo,jimberlage/servo,nnethercote/servo,dsandeephegde/servo,jimberlage/servo,dsandeephegde/servo,pyfisch/servo,fiji-flo/servo,thiagopnts/servo,SimonSapin/servo,cbrewster/servo,sadmansk/servo,dsandeephegde/servo,anthgur/servo,notriddle/servo,KiChjang/servo,SimonSapin/servo,thiagopnts/servo,sadmansk/servo,eddyb/servo,peterjoel/servo,saneyuki/servo,mattnenterprise/servo,DominoTree/servo,emilio/servo,upsuper/servo,canaltinova/servo,dati91/servo,szeged/servo,szeged/servo,peterjoel/servo,peterjoel/servo,cbrewster/servo,thiagopnts/servo,mattnenterprise/servo,canaltinova/servo,notriddle/servo,thiagopnts/servo,peterjoel/servo,paulrouget/servo,saneyuki/servo,pyfisch/servo,paulrouget/servo,notriddle/servo,avadacatavra/servo,rnestler/servo,thiagopnts/servo,mbrubeck/servo,szeged/servo,dati91/servo,dsandeephegde/servo,rnestler/servo,jimberlage/servo,notriddle/servo,nnethercote/servo,splav/servo,dati91/servo,thiagopnts/servo,rnestler/servo,mattnenterprise/servo,dati91/servo,CJ8664/servo,eddyb/servo,upsuper/servo,splav/servo,ConnorGBrewster/servo,fiji-flo/servo,nrc/servo,fiji-flo/servo,emilio/servo,anthgur/servo,ConnorGBrewster/servo,canaltinova/servo,notriddle/servo,cbrewster/servo,emilio/servo,paulrouget/servo,anthgur/servo,nnethercote/servo,nnethercote/servo,rnestler/servo,canaltinova/servo,szeged/servo,larsbergstrom/servo,peterjoel/servo,SimonSapin/servo,emilio/servo,mattnenterprise/servo,mattnenterprise/servo,rnestler/servo,jimberlage/servo,DominoTree/servo,szeged/servo,eddyb/servo,CJ8664/servo,pyfisch/servo,peterjoel/servo,rnestler/servo,larsbergstrom/servo,eddyb/servo,sadmansk/servo,peterjoel/servo,saneyuki/servo,jimberlage/servo,notriddle/servo,SimonSapin/servo,nnethercote/servo,mbrubeck/servo,larsbergstrom/servo,szeged/servo,fiji-flo/servo,cbrewster/servo,fiji-flo/servo,KiChjang/servo,DominoTree/servo,larsbergstrom/servo,fiji-flo/servo,CJ8664/servo,pyfisch/servo,canaltinova/servo,avadacatavra/servo,notriddle/servo,CJ8664/servo,paulrouget/servo,pyfisch/servo,saneyuki/servo,mbrubeck/servo,upsuper/servo,saneyuki/servo,szeged/servo,szeged/servo,mbrubeck/servo,sadmansk/servo,splav/servo,pyfisch/servo,larsbergstrom/servo,nrc/servo,CJ8664/servo,canaltinova/servo,splav/servo,eddyb/servo,SimonSapin/servo,avadacatavra/servo,anthgur/servo,ConnorGBrewster/servo,cbrewster/servo,DominoTree/servo,DominoTree/servo,paulrouget/servo,ConnorGBrewster/servo,ConnorGBrewster/servo,splav/servo,notriddle/servo,SimonSapin/servo,peterjoel/servo,SimonSapin/servo,dsandeephegde/servo,nrc/servo,dati91/servo,peterjoel/servo,saneyuki/servo,DominoTree/servo,saneyuki/servo,cbrewster/servo,saneyuki/servo,cbrewster/servo,nnethercote/servo,cbrewster/servo,saneyuki/servo,ConnorGBrewster/servo,paulrouget/servo,splav/servo,jimberlage/servo,KiChjang/servo,mbrubeck/servo,CJ8664/servo,nnethercote/servo,jimberlage/servo,thiagopnts/servo,DominoTree/servo,rnestler/servo,canaltinova/servo,eddyb/servo,larsbergstrom/servo,canaltinova/servo,avadacatavra/servo,paulrouget/servo,saneyuki/servo,upsuper/servo,avadacatavra/servo,CJ8664/servo,pyfisch/servo,anthgur/servo,KiChjang/servo,ConnorGBrewster/servo,KiChjang/servo,larsbergstrom/servo,upsuper/servo,nnethercote/servo,dati91/servo,notriddle/servo,paulrouget/servo,DominoTree/servo,notriddle/servo,KiChjang/servo,pyfisch/servo