each feign client has a separate httpclient/okhttp
- create an interface, then annotated with @MultiFeignClient
- register client, and specify the bean name in @MultiFeignClient
2.1 register a customized okhttp client(if you use ClientPoolTypeEnum.OK_HTTP in @MultiFeignClient) in Spring
2.2 register a customized http client(if you use ClientPoolTypeEnum.HTTP_CLIENT in @MultiFeignClient) in Spring - using @RequestLine to annotate method