@Buzzardo Plz review it🙇🏻

Hi @zeze1004. Thanks for the PR and the issue.

Rather than changing this in the code, I'd prefer to see a note admonition in the Run the Application section that specifies the dependency required in Gradle and Maven, if applicable.

Because our guides are designed to be very basic, we try not to add any code that we do not explain. This is a complex issue and has generated discussion in Spring Boot, Reactor Netty, and Netty projects. As such, it isn't one that I want to explain in a 'hello world' guide, so I'd prefer it not be in the code. A second reason not to add this in the code is that we would need to add it multiple times in the initial and complete folders. A third reason is maintenance. If this dependency is not required in future versions, I'd rather have the README be out of date than have code in our sample that we forget to remove.

If you'd like to contribute a note to the README, please feel free. I'll leave this PR and issue open for contribution. Note that this guide went through a rewrite recently so this PR now has conflicts.