Execution example::

  tokenize TokenMecab "東京都"
  # [
  #   [
  #     -22, 
  #     1337566253.89858, 
  #     0.000355720520019531, 
  #     "[tokenize] nonexistent tokenizer: <TokenMecab>", 
  #     [
  #       [
  #         "create_lexicon_for_tokenize", 
  #         "proc_tokenize.c", 
  #         139
  #       ]
  #     ]
  #   ]
  # ]
