* [TOKEN_DELIMITERS]. Returns null if the buffer is empty or prefixed with a delimiter.
 */
private fun Buffer.readToken(): String? {
  var tokenSize = indexOfElement(TOKEN_DELIMITERS)
  if (tokenSize == -1L) tokenSize = size

  return when {
    tokenSize != 0L -> readUtf8(tokenSize)
    else -> null
  }
}

fun CookieJar.receiveHeaders(
  url: HttpUrl,
  headers: Headers,
) {