We'll create fresh WordPress site with Plugin Name: iBryl Switch User installed. You have 20 minutes to test the plugin after that site we'll be deleted.
This plugin can to quickly switch user by click. It is comfortable for develop themes and plugins.
After load page, loading neat closed sidebar from right. By click on arrow it show or hide sidebar. Sidebar is
displaying all registered WordPress users. By click on user is ajax send user ID to back end where switch user.
After response is JavaScript reload page with registered new user.