Avoid lots of lookups to process.env
Avoid lots of lookups to process.env

See b85bf633 for details - process.env results in a synchronous syscall
to `getenv()` and this was happening at least a few times per request.

Aloomaio/request,robu3/request,calibr/request,watson/request,mvnnn/request,cvibhagool/request,request/request,h1bomb/request,IveWong/request,jzaefferer/request,MofeLee/request,robu3/request,linalu1/request,whembed197923/request,zodsoft/request,kevinburke/request,sean3z/request,nishant8BITS/request,NewGyu/request,blabno/request,calibr/request,Jonekee/request,watson/request,Codelegant92/request,pho3nixf1re/request,HAKASHUN/request,niklabh/request,LoicMahieu/request,wangchi/request,beni55/request,xiwc/request,sean3z/request,wakermahmud/request,jsifuentes/request,nishant8BITS/request,ryanwholey/request,djchie/request,lxe/request,kublaj/request,HAKASHUN/request,whembed197923/request,IbpTeam/node-request,Prasanna-sr/request,wangchi/request,blabno/request,seegno-forks/request,longwenjunjie/request,IveWong/request,faradayio/request,chaoliu/request,wakermahmud/request,MofeLee/request,pho3nixf1re/request,paulomcnally/request,udp/request,h1bomb/request,kublaj/request,motopia/request,ryanwholey/request,IbpTeam/node-request,lalitkapoor/request,czardoz/request,zhouweiming/request,kevinburke/request,zhouweiming/request,pablobrady/request,zodsoft/request,rbramwell/request,xtidt/request,NewGyu/request,Prasanna-sr/request,lxe/request,mvnnn/request,manishnakar/request,kmulvey/request,beni55/request,xtidt/request,jzaefferer/request,lalitkapoor/request,djchie/request,cvibhagool/request,manishnakar/request,simov/request,czardoz/request,motopia/request,rbramwell/request,xiwc/request,pablobrady/request,jsifuentes/request,Codelegant92/request,request/request,paulomcnally/request,not001praween001/request,faradayio/request,phillipj/request,Jonekee/request,neo-z/request,longwenjunjie/request,neo-z/request,chaoliu/request,not001praween001/request,niklabh/request,LoicMahieu/request,simov/request,phillipj/request,linalu1/request,kmulvey/request,seegno-forks/request,udp/request,Aloomaio/request