docs: def replay_checker(self, callback):
          """
          Decorate a method that receives the request headers and returns a bool
          indicating whether we should proceed with the request. This can be used
          to protect against replay attacks. For example, this method could check
          the request date header value is within a delta value of the server time.
          """
          if not callback or not callable(callback):
              raise Exception("Please pass in a callable that protects against replays")
          self.replay_checker_callback = callback
          return callback