Execution example::

  tokenize TokenDelimitNull "Groonga\u0000full-text-search\u0000HTTP" NormalizerAuto
  # [
  #   [
  #     0, 
  #     1337566253.89858, 
  #     0.000355720520019531
  #   ], 
  #   [
  #     {
  #       "position": 0, 
  #       "value": "groongau0000full-text-searchu0000http"
  #     }
  #   ]
  # ]
