function readRecord() {
    if (index >= text.length) {
      return EOF;
    }
    const record = [];
    for (let field = readField(); field != EOR; field = readField()) {
      record.push(field);
    }
    return record;
  }
Read the next record.
@return {!Array<string>|!goog.labs.format.csv.Sentinels_} A single record
    with multiple fields.