一次rpc调用如何指定全局参数,rpc上下文需要调用一次指定一次,需求是全局有效的

- [ ] I have searched the [issues](https://github.com/apache/dubbo/issues) of this repository and believe that this is not a duplicate.

## Ask your question here

Start with Dubbo's RPC context and the issue's existing discussion to determine whether parameters should apply globally or per invocation. Document the intended scope and acceptance criteria before identifying the relevant implementation entry points; the issue does not name any files or tests.

Written by the indexing model from the issue text.