docs: public int deleteFile(String fullFilename) {
          int result = 1;
          TrackerServer trackerServer = null;
          StorageClient1 storageClient1 = null;
          try {
              trackerServer = fastDfsClientPool.borrowObject();
              storageClient1 = new StorageClient1(trackerServer, null);
              result = storageClient1.deleteFile1(fullFilename);
          } catch (Exception e) {
              throw Lang.makeThrow("[FastdfsService] delete file error : %s", e.getMessage());
          } finally {
              if (trackerServer != null)
                  fastDfsClientPool.returnObject(trackerServer);
              storageClient1 = null;
          }
          return result;
      }