method
    
    thread
  thread(algorithm, search_keys, charset)
  public
  As for #search(), but returns message sequence numbers in threaded format, as a Net::IMAP::ThreadMember tree. The supported algorithms are:
ORDEREDSUBJECT  | 
 split into single-level threads according to subject,  | 
ordered by date.
REFERENCES  | 
 split into threads by parent/child relationships determined  | 
by which message is a reply to which.
Unlike #search(), charset is a required argument. US-ASCII and UTF-8 are sample values.
See [SORT-THREAD-EXT] for more details.

  
  
  