def expired?(request, method)
      if (expires_at = request.expires_at) && expires_at > 0 && (now = Time.now.to_i) >= expires_at
        @reject_stats.update("expired (#{method})")
        Log.info("REJECT EXPIRED <#{request.token}> from #{request.from} TTL #{RightSupport::Stats.elapsed(now - expires_at)} ago")
        # For agents that do not know about non-delivery, use error result
        if can_handle_non_delivery_result?(request.recv_version)
          OperationResult.non_delivery(OperationResult::TTL_EXPIRATION)
        else
          OperationResult.error("Could not deliver request (#{OperationResult::TTL_EXPIRATION})")
        end
      end
    end
def expired?(request, method)
      if (expires_at = request.expires_at) && expires_at > 0 && (now = Time.now.to_i) >= expires_at
        @reject_stats.update("expired (#{method})")
        Log.info("REJECT EXPIRED <#{request.token}> from #{request.from} TTL #{RightSupport::Stats.elapsed(now - expires_at)} ago")
        # For agents that do not know about non-delivery, use error result
        if can_handle_non_delivery_result?(request.recv_version)
          OperationResult.non_delivery(OperationResult::TTL_EXPIRATION)
        else
          OperationResult.error("Could not deliver request (#{OperationResult::TTL_EXPIRATION})")
        end
      end
    end
Determine if request TTL has expired

 === Parameters
 request(Push|Request):: Request to be checked
 method(String):: Actor method requested to be performed

 === Return
 (OperationResult|nil):: Error result if expired, otherwise nil