arrayOfNulls<DateFormat>(BROWSER_COMPATIBLE_DATE_FORMAT_STRINGS.size)

/** Returns the date for this string, or null if the value couldn't be parsed. */
fun String.toHttpDateOrNull(): Date? {
  if (isEmpty()) return null

  val position = ParsePosition(0)
  var result = STANDARD_DATE_FORMAT.get().parse(this, position)
  if (position.index == length) {
    // STANDARD_DATE_FORMAT must match exactly; all text must be consumed, e.g. no ignored