call (Rack::MethodOverride)

    # File lib/rack/methodoverride.rb, line 12
        def call(env)
          if env["REQUEST_METHOD"] == "POST"
            req = Request.new(env)
            method = req.POST[METHOD_OVERRIDE_PARAM_KEY] ||
              env[HTTP_METHOD_OVERRIDE_HEADER]
            method = method.to_s.upcase
            if HTTP_METHODS.include?(method)
              env["rack.methodoverride.original_method"] = env["REQUEST_METHOD"]
              env["REQUEST_METHOD"] = method
            end
          end

          @app.call(env)
        end