custom data of the #CamelFolderSummary descendants
count of deleted messages
folder flags
name of the folder
count of junk and not deleted messages
count of junk messages
next free uid
count of all messages
timestamp of the summary
count of unread messages
version of the saved information
count of visible (not deleted and not junk) messages
Values to store/load for single folder's #CamelFolderSummary structure.