Index: Lib/httplib.py
===================================================================
--- Lib/httplib.py	(revision 67120)
+++ Lib/httplib.py	(working copy)
@@ -734,10 +734,17 @@
 
         Appends an extra \\r\\n to the buffer.
         """
+        self.send(self._get_output())
+
+    def _get_output(self):
+        """Get the currently buffered request and clear the buffer.
+
+        Appends an extra \\r\\n to the buffer.
+        """
         self._buffer.extend(("", ""))
         msg = "\r\n".join(self._buffer)
         del self._buffer[:]
-        self.send(msg)
+        return msg
 
     def putrequest(self, method, url, skip_host=0, skip_accept_encoding=0):
         """Send a request to the server.
@@ -857,16 +864,29 @@
         str = '%s: %s' % (header, value)
         self._output(str)
 
-    def endheaders(self):
-        """Indicate that the last header line has been sent to the server."""
-
+    def endheaders(self, extra_data=None):
+        """Indicate that the last header line has been sent to the server.
+        The optional extra_data is data that is sent afther the headers, and
+        can be either a string or a file-like object.  It will be appended
+        to the header data and all sent in one chunk if possible.
+        This helps avoid the dreaded Nagle/delayed-ACK TCP performance
+        problem that can be caused by two send operations in a row.
+        """
         if self.__state == _CS_REQ_STARTED:
             self.__state = _CS_REQ_SENT
         else:
             raise CannotSendHeader()
+        if extra_data is not None:
+            if isinstance(extra_data, str):
+                self.send(self._get_output() + extra_data)
+            else:
+                #if extra_data is a file, we have to live with risking
+                #the Nagle problem
+                self._send_output()
+                self.send(extra_data)
+        else:
+            self._send_output()
 
-        self._send_output()
-
     def request(self, method, url, body=None, headers={}):
         """Send a complete request to the server."""
 
@@ -908,11 +928,8 @@
                 self.putheader('Content-Length',thelen)
         for hdr, value in headers.iteritems():
             self.putheader(hdr, value)
-        self.endheaders()
+        self.endheaders(body)
 
-        if body:
-            self.send(body)
-
     def getresponse(self):
         "Get the response from the server."
 
Index: Lib/test/test_xmlrpc.py
===================================================================
--- Lib/test/test_xmlrpc.py	(revision 67120)
+++ Lib/test/test_xmlrpc.py	(working copy)
@@ -405,6 +405,9 @@
                 # protocol error; provide additional information in test output
                 self.fail("%s\n%s" % (e, getattr(e, "headers", "")))
 
+            
+            
+
     def test_introspection2(self):
         try:
             # test _methodHelp()
@@ -647,7 +650,9 @@
     # 10035 (WSAEWOULDBLOCK) in the server thread handle_request call when
     # run on Windows. This only happens on the first test to run, but it
     # fails every time and so these tests are skipped on win32 platforms.
-    if sys.platform != 'win32':
+    # Update, nov 2008:  This appears no longer to be the case, so they
+    # are included regardless
+    if True or sys.platform != 'win32':
         xmlrpc_tests.append(SimpleServerTestCase)
         xmlrpc_tests.append(FailingServerTestCase)
         xmlrpc_tests.append(CGIHandlerTestCase)
Index: Lib/xmlrpclib.py
===================================================================
--- Lib/xmlrpclib.py	(revision 67120)
+++ Lib/xmlrpclib.py	(working copy)
@@ -1234,6 +1234,8 @@
         self.send_user_agent(h)
         self.send_content(h, request_body)
 
+        #we will perform readline() on the h.getfile() so we need
+        #default buffering
         errcode, errmsg, headers = h.getreply()
 
         if errcode != 200:
@@ -1249,7 +1251,6 @@
             sock = h._conn.sock
         except AttributeError:
             sock = None
-
         return self._parse_response(h.getfile(), sock)
 
     ##
@@ -1346,9 +1347,7 @@
     def send_content(self, connection, request_body):
         connection.putheader("Content-Type", "text/xml")
         connection.putheader("Content-Length", str(len(request_body)))
-        connection.endheaders()
-        if request_body:
-            connection.send(request_body)
+        connection.endheaders(request_body)
 
     ##
     # Parse response.