docs: public BoxRequestsFile.DownloadThumbnail getDownloadThumbnailRequest(File target, String fileId) throws IOException{
          if (!target.exists()){
              throw new FileNotFoundException();
          }
          if (target.isDirectory()){
              throw new RuntimeException("This endpoint only supports files and does not support directories");
          }
          BoxRequestsFile.DownloadThumbnail request = new BoxRequestsFile.DownloadThumbnail(fileId, target, getThumbnailFileDownloadUrl(fileId), mSession);
          return request;
      }