instance method call

# File actionpack/lib/action_dispatch/middleware/rescue.rb, line 9
    def call(env)
      @app.call(env)
    rescue Exception => exception
      if rescuer = @rescuers[exception.class.name]
        env['action_dispatch.rescue.exception'] = exception
        rescuer.call(env)
      else
        raise exception
      end
    end