docs: public NodeInterval findNode(final SearchCallback callback) {
  
          Preconditions.checkNotNull(callback);
          if (callback.isMatch(this)) {
              return this;
          }
  
          NodeInterval curChild = leftChild;
          while (curChild != null) {
              final NodeInterval result = curChild.findNode(callback);
              if (result != null) {
                  return result;
              }
              curChild = curChild.getRightSibling();
          }
          return null;
      }