Templates should not output any content to the client side when a sendRedirect has been called

Some container (like Jetty 8.1.9) will generate a warning in the logs when this happens and the spec says it shouldn't happen, see:

http://docs.oracle.com/javaee/6/api/javax/servlet/http/HttpServletResponse.html#sendRedirect(String)

"After using this method, the response should be considered to be committed and should not be written to."