Sorting method on messages.
Declarations
Type
one of "date", "date-received", "from", "mailbox-order", "score", "size", "spam", "subject", "threads", "to", "reverse-date", "reverse-date-received", "reverse-from", "reverse-mailbox-order", "reverse-score", "reverse-size", "reverse-spam", "reverse-subject", "reverse-threads", "reverse-to"Default
"threads"