stream: inline and simplify onwritedrain

Inline and simplify onwritedrain. Also remove comment that seems to be outdated/invalid. PR-URL: #29037 Reviewed-By: Luigi Pinca <[email protected]> Reviewed-By: Matteo Collina <[email protected]> Reviewed-By: Trivikram Kamat <[email protected]> Reviewed-By: Rich Trott <[email protected]>

Author: ronag

lib/_stream_writable.js

@@ -478,21 +478,13 @@ function onwrite(stream, er){
 }
 
 functionafterWrite(stream,state,finished,cb){
-if(!finished)
-onwriteDrain(stream,state);
-state.pendingcb--;
-cb();
-finishMaybe(stream,state);
-}
-
-// Must force callback to be called on nextTick, so that we don't
-// emit 'drain' before the write() consumer gets the 'false' return
-// value, and has a chance to attach a 'drain' listener.
-functiononwriteDrain(stream,state){
-if(state.length===0&&state.needDrain){
+if(!finished&&state.length===0&&state.needDrain){
 state.needDrain=false;
 stream.emit('drain');
 }
+state.pendingcb--;
+cb();
+finishMaybe(stream,state);
 }
 
 // If there's something in the buffer waiting, then process it