public FolderId FindFolderIdByShortName( FolderId parentFolderId, string folderName )
Public Function FindFolderIdByShortName ( parentFolderId As FolderId, folderName As String ) As FolderId
parentFolderId must be the immediate parent of folderName folder. Also, folderName must be a short name (not a full name with nested folder names in it).
Key difference of this method from DownloadFolderByShortName(FolderId, String) is that it returns just ID. This means that MailBee requests less info from the server making this method a bit more efficient. However, if you need the detailed info about the folder (e.g. message count, unseen count, etc), use DownloadFolderByShortName(FolderId, String) instead.