def handle?(req)
      if @opts.key?(:if)
        cond = @opts[:if]
        cond = cond.call(req) if cond.respond_to?(:call)
        return cond
      end
      true
    end
def handle?(req)
      if @opts.key?(:if)
        cond = @opts[:if]
        cond = cond.call(req) if cond.respond_to?(:call)
        return cond
      end
      true
    end
Returns false if the current request should
 not be handled by the middleware