Simplify a few internal HTTP events.

lib/http.js

@@ -411,7 +411,7 @@ OutgoingMessage.prototype.write = function (chunk, encoding) {
 };
 
 OutgoingMessage.prototype.flush = function () {
-  this.emit("flush");
+  this._onFlush();
 };
 
 OutgoingMessage.prototype.finish = function () {
@@ -566,7 +566,6 @@ function flushMessageQueue (socket, queue) {
 
     if (!message.finished) break;
 
-    message.emit("sent");
     queue.shift();
 
     if (message.closeOnFinish) return true;
@@ -664,11 +663,11 @@ function connectionListener (socket) {
     var res = new ServerResponse(req);
 
     res.shouldKeepAlive = shouldKeepAlive;
-    res.addListener('flush', function () {
+    res._onFlush = function () {
       if (flushMessageQueue(socket, responses)) {
         socket.end();
       }
-    });
+    };
     responses.push(res);
 
     self.emit('request', req, res);
@@ -716,7 +715,7 @@ function Client ( ) {
   };
 
   self._pushRequest = function (req) {
-    req.addListener("flush", function () {
+    req._onFlush = function () {
       if (self.readyState == "closed") {
         debug("HTTP CLIENT request flush. reconnect.  readyState = " + self.readyState);
         self._reconnect();
@@ -725,7 +724,7 @@ function Client ( ) {
 
       debug("self flush  readyState = " + self.readyState);
       if (req == currentRequest) flushMessageQueue(self, [req]);
-    });
+    };
     requests.push(req);
   };