https://docs.spring.io/spring-framework/docs/5.3.0-SNAPSHOT/spring-framework-reference/web-reactive.html#webflux-client

2024
DanVega - Getting Started with the Web Client in Spring Boot & Writing Tests 0:00 of 31:30
    https://www.youtube.com/watch?v=0jyKgEz0Yn8
2021
https://habr.com/ru/company/otus/blog/541404/
    https://github.com/stanislaw-wein/spring-boot-web-client-examples