public FCP2Upload Upload(FCP2Key key, FileInfo file)
 {
     return  new FCP2Upload();
 }
 internal FCP2Download(FCP2Key key, FileInfo file)
 {
     Key = key;
     File = file;
 }
 public FCP2Download Download(FCP2Key key)
 {
     return new FCP2Download(key, null);
 }