def defrag

      raise(NotImplementedError.new(
        "method defrag is supported since Tokyo Cabinet 1.4.21. " +
        "your TC version doesn't support it"
      )) unless lib.respond_to?(:tctdbsetdfunit)

      call_misc('defrag', Rufus::Tokyo::List.new)
    end
def defrag

      raise(NotImplementedError.new(
        "method defrag is supported since Tokyo Cabinet 1.4.21. " +
        "your TC version doesn't support it"
      )) unless lib.respond_to?(:tctdbsetdfunit)

      call_misc('defrag', Rufus::Tokyo::List.new)
    end
Triggers a defrag run (TC >= 1.4.21 only)