-1L -> skip(buffer.size) // Exhaust this source.
    else -> skip(newline + 1)
  }
}

/**
 * Reads lines from `IdnaMappingTable.txt`.
 *
 * Comment lines are either blank or start with a `#` character. Lines may also end with a comment.
 * All comments are ignored.
 *
 * Regular lines contain fields separated by semicolons.
 *