I have a method, where I use the deprecated WebClient class to upload a file to a FTP Server.

public async Task<BaseResponse<Void>> Handle(FTPUploadRequest request, CancellationToken cancellationToken)
{
    using WebClient client = new()
    {
        Credentials = new NetworkCredential(configuration.FTP.User, configuration.FTP.Password.Decrypt())
    };

   static string BuildUri(FTPUploadRequest request, IOptionsSnapshot<Configuration> configuration) 
       => $"ftp://{configuration.FTP.Server}/{request.DirectoryPath}/{request.FileName}";

   client.UploadFile(
       BuildUri(request, configuration),
       WebRequestMethods.Ftp.UploadFile,
       request.FilePath + "/" + request.FileName);

   return await BaseResponse<Void>.Create(true);
}

WebClient is deprecated and not Unit-testable. So I wanted to inject IHttpClientFactory which is also stated in the deprecation-message. I can easily do that, but how should I upload the file? Posting against a FTP Server with a multi-part-message?

I have no idea and cannot find any solution on the internet. Downloading from a FTP Server is more easy by just using Get and having the file path with basic authentication. But uploading is more challenging.

Any Ideas?