Remote Procedure Call (RPC)

https://github.com/apache/incubator-brpc/blob/master/community/cases.md

针对这个文件，提交PR，然后找我review即可。

更新过程：

1. 开一个issue，名字不妨为“xxx公司的brpc落地场景“
2. 修改这个文件（cases.md)
3. 提交PR

Let's support at least reading "b3" header from a single string, most commonly traceid-spanid-1
It would also be nice to support optionally writing this, especially in message providers or others with constrained environments.

Expected behavior

As discussed on openzipkin/b3-propagation#21 and first implemented here: https://github.com/openzipkin/brave/blob/master/brave/src/main/java/bra

We hope mores developers join CloudWeGo. This is a task issue which need your help.

Issue Description
Write a business demo code use Kitex, which can guide users how to use Kitex.
Please submit your code to https://github.com/cloudwego/kitex-examples/bizdemo/{yourdemo}.

Picked

• TODO by @longlihale
• TODO by @L0uisJ0shua

@trustin suggested an awesome idea to write a StreamMessage<T> into a File or Path. line/armeria#4044 (comment)

interface StreamMessage<T> {
    default CompletableFuture<Void> writeTo(Path destination, Function<? super T, ? extends HttpData> mapper, options...) {
        // Delegate to StreamMessages.writeTo(...)
    }
}