/// <summary>
        /// Create folder
        /// </summary>
        /// <param name="folderName"></param>
        /// <param name="exchangeService"></param>
        /// <returns></returns>
        internal static async Task<MailFolder> CreateFolder(string folderName, ExchangeService exchangeService, WellKnownFolderName folderRoot)
        {
            MailFolder folder = new MailFolder(exchangeService);
            folder.DisplayName = folderName;
            MailFolder mailFolderRoot = await exchangeService.GetAsync<MailFolder>(
                new EntityPath(
                    folderRoot.ToString(), 
                    typeof(MailFolder)));

            await  folder.SaveAsync(mailFolderRoot);
            return folder;
        }
        static void MoveFolder(ExchangeService service, string DisplayName, WellKnownFolderName SourceFolder, WellKnownFolderName DestinationFolder)
        {
            // Attempt to retrieve the unique identifier of the folder with the specified display name (DisplayName) within the specified folder (SourceFolder).
            FolderId folderId = Ex15_FindFolderIdByDisplayName_CS.FindFolderIdByDisplayName(service, DisplayName, SourceFolder);

            if (folderId != null)
            {
                // Bind to the folder by using its unique identifier.
                Folder folder = Folder.Bind(service, folderId);

                // Move the folder from its current location into the specified location (DestinationFolder).
                Folder newFolder = folder.Move(DestinationFolder);

                Console.WriteLine("Folder '" + DisplayName + "' has been moved to the '" + DestinationFolder.ToString() + "' folder.");
            }
            else
            {
                Console.WriteLine("Folder '" + DisplayName + "' could not be found in the '" + SourceFolder + "' folder.");
            }
        }
 /// <summary>
 /// Create new instance of <see cref="FolderId"/> base on <see cref="WellKnownFolderName"/> and mailbox.
 /// </summary>
 /// <param name="wellKnownFolderName">Well known folder name.</param>
 /// <param name="mailbox">MailboxId.</param>
 public FolderId(WellKnownFolderName wellKnownFolderName, string mailbox)
     : this(wellKnownFolderName.ToString(), mailbox)
 {
 }