code: @Override
      public void delete(String spaceId, String key, IDeleteCallback callback) {
          try {
              doDelete(spaceId, key);
              if (callback != null) {
                  callback.onSuccess(spaceId, key);
              }
          } catch (Throwable t) {
              if (callback != null) {
                  callback.onError(spaceId, key, t);
              }
          }
      }
docs: {@inheritDoc}