    def size
      if defined?(::Delayed::Backend::Mongoid::Job) && Delayed::Worker.backend == Delayed::Backend::Mongoid::Job
        query = greater_than_priority ? Delayed::Job.gte(priority: priority) : Delayed::Job.lte(priority: priority)
      else
        operator = greater_than_priority ? ">=" : "<="
        query = Delayed::Job.where("priority #{operator} ?", priority)
      end
      opts = {}
      opts[:queue] = queue if queue
      opts[:locked_at] = nil unless include_locked
      opts[:last_error] = nil unless include_errored
      query.where(opts).count
    end