def call(env)
      if env['REQUEST_METHOD'] == 'GET' && env['PATH_INFO'] == logout_path(env)
        ::Rack::Response.new(login_html(env, :logged_out => true)) do |resp|
          resp['Content-Type'] = 'text/html'
        end.finish
      else
        @app.call(env)
      end
    end
def call(env)
      if env['REQUEST_METHOD'] == 'GET' && env['PATH_INFO'] == logout_path(env)
        ::Rack::Response.new(login_html(env, :logged_out => true)) do |resp|
          resp['Content-Type'] = 'text/html'
        end.finish
      else
        @app.call(env)
      end
    end
When given `GET` to the configured logout path, builds a Rack
 response containing the login form with a "you have been logged
 out" notification.  Otherwise, passes the response on.

 @return a finished Rack response