_transform(chunk, encoding, done) {
    try {
      this.tokenizer.write(chunk);
      done();
    } catch (err) {
      done(err);
    }
  }
Main function that send data to the parse to be processed.

@param {Buffer} chunk Incoming data
@param {String} encoding Encoding of the incoming data. Defaults to 'utf8'
@param {Function} done Called when the proceesing of the supplied chunk is done