protected void issueRedirect(ServletRequest request, ServletResponse response, String redirectUrl) throws Exception {
        WebUtils.issueRedirect(request, response, redirectUrl);
    }
Issues an HTTP redirect to the specified URL after subject logout.  This implementation simply calls
{@code WebUtils.}{@link WebUtils#issueRedirect(javax.servlet.ServletRequest, javax.servlet.ServletResponse, String)
issueRedirect(request,response,redirectUrl)}.

@param request     the incoming Servlet request
@param response    the outgoing Servlet response
@param redirectUrl the URL to where the browser will be redirected immediately after Subject logout.
@throws Exception if there is any error.
web/src/main/java/org/apache/shiro/web/filter/authc/LogoutFilter.java