help request: How can we maintain the original order of the JSON parameters in the request body after processing the API request via Apisix

### Description

How can we maintain the original order of the JSON parameters in the request body after processing the API request via Apisix? For example, the original request parameters are: {"b":11,"a":2}. Now, after processing via Apisix, sometimes they become {"a":2,"b":11}. We need to keep the original order {"b":11,"a":2}.

### Environment

- APISIX version (run `apisix version`):
- Operating system (run `uname -a`):
- OpenResty / Nginx version (run `openresty -V` or `nginx -V`):
- etcd version, if relevant (run `curl http://127.0.0.1:9090/v1/server_info`):
- APISIX Dashboard version, if relevant:
- Plugin runner version, for issues related to plugin runners:
- LuaRocks version, for installation issues (run `luarocks --version`):

No source file or test is identified. Start by reproducing the request through APISIX with {"b":11,"a":2}, then trace the request-body processing path to identify where ordering changes. Done means confirming whether APISIX can preserve the original parameter order and documenting the resulting behavior or required change.

Written by the indexing model from the issue text.