Final example

Program.cs

 static void Main()
        {
            var folderName = "pdf-demo";
            var localFolder = $@"C:\asposedemo\{folderName}\";
            var fileExistResponse = _storageApi.GetIsExist(new GetIsExistRequest(folderName, null, storageName));
            if (fileExistResponse.Code == 200)
                if (fileExistResponse.FileExist.IsFolder == false)
                {
                    var createFolderResponse = _storageApi.PutCreateFolder(new PutCreateFolderRequest(folderName, null, storageName));
                    if (createFolderResponse.Code != 200)
                    {
                        Console.WriteLine("CreateFolder response is not OK!");
                        Console.WriteLine(createFolderResponse.ToString());
                        return;
                    }
                }
                else
                {
                    var filesResponse = _storageApi.GetListFiles(new GetListFilesRequest(folderName, storageName));
                    if (filesResponse.Code == 200)
                    {
                        var filesInCloudFolder = filesResponse.Files.Where(f => f.IsFolder == false).Select(item => item.Name).ToList();
                        var filesInLocalFodler = new DirectoryInfo(localFolder).GetFiles().Select(fi => fi.Name);
                        foreach (var fileName in filesInLocalFodler.Except(filesInCloudFolder))
                        {
                            Console.WriteLine($"Uploading {fileName}");
                            var fileStream = new FileStream($@"{localFolder}\{fileName}", FileMode.Open);
                            var uploadResponse = _storageApi.PutCreate(new PutCreateRequest($"/{folderName}/{fileName}", fileStream));
                        }
                    }                    
                }
            else
            {
                Console.WriteLine("FileExist response response is not OK!");
                Console.WriteLine(fileExistResponse.ToString());
            }
        }