code: @Override
      public long getFileSize() {
          try {
              final rh_protoClient client = getRpcClient(OncRpcProtocols.ONCRPC_UDP);
              try {
                  return BlockingWrapper.execute(() -> client.getFileSize_1());
              } finally {
                  client.close();
              }
          } catch (OncRpcException | IOException | InterruptedException | RuntimeException ex) {
              LOG.log(Level.SEVERE, "getFileSize RPC call failed", ex);
              throw new RuntimeException("RPC call failed", ex);
          }
      }
docs: Check disk space usage (bytes).
  
  @return The disk space used for storing metrics.