docs: @Override
      public void addUpdate(NDArrayMessage array) {
          UnsafeBuffer directBuffer = (UnsafeBuffer) NDArrayMessage.toBuffer(array);
          byte[] data = directBuffer.byteArray();
          if (data == null) {
              data = new byte[directBuffer.capacity()];
              directBuffer.getBytes(0, data, 0, data.length);
          }
          byte[] key = ByteBuffer.allocate(4).putInt(size).array();
          try {
              db.put(key, data);
          } catch (RocksDBException e) {
              throw new RuntimeException(e);
          }
  
          size++;
  
      }