fix the "write after end" error when in stream mode

Author: codingfishman

lib/requestHandler.js

@@ -159,7 +159,7 @@ function fetchRemoteResponse(protocol, options, reqData, config) {
 
       res.on('end', () => {
         if (resDataStream) {
-          resDataStream.emit('end'); // EOF
+          resDataStream.push(null); // indicate the stream is end
         } else {
           finishCollecting();
         }