docs: public String render(Map<String, Object> context) {
  
          LiquidWalker walker = new LiquidWalker(new CommonTreeNodeStream(root), this.tags, this.filters, this.flavor);
  
          try {
              LNode node = walker.walk();
              Object rendered = node.render(context);
              return rendered == null ? "" : String.valueOf(rendered);
          }
          catch (Exception e) {
              throw new RuntimeException(e);
          }
      }