Disable proxying on COMET responses

@@ -76,6 +76,7 @@ public class CometMessengerServlet extends HttpServlet implements CometProcessor
         HttpServletRequest request = event.getHttpServletRequest();
         HttpServletResponse response = event.getHttpServletResponse();
         response.setContentType("application/json");
+        response.setHeader("X-Accel-Buffering", "No");
         if (event.getEventType() == CometEvent.EventType.BEGIN) {
             Debug.logInfo("Begin for session: " + request.getSession(true).getId(), module);
             PrintWriter writer = response.getWriter();