Is it still needed to use JvmField annotation for ISSUE instance?

Hello.

I tried to create my custom line rule.
And I have a question while writing it.

In [Creating the issue](https://googlesamples.github.io/android-custom-lint-rules/api-guide.html#writingalintcheck:basics/creatinganissue) section, sample code shows that `JvmField` annotation is using for `ISSUE` instance.

But in my understand, it seems that `JvmField` annotation is not required to [Registering the issue](https://googlesamples.github.io/android-custom-lint-rules/api-guide.html#writingalintcheck:basics/registeringtheissue).

And also, I tried to remove `JvmField` annotation from [SampleCodeDetector of HEAD](https://github.com/ganadist/android-custom-lint-rules/commit/69e66d8), but it seems to be worked well at `:app:lintDebug` task or Android Studio.

Gradle scan output:
https://scans.gradle.com/s/dmijqsoka624a/console-log?page=1#L178

Is it okay to remove `JvmField` annotation for my custom lint rules?
Or please describe why `JvmField` annotation is required at [Creating the issue](https://googlesamples.github.io/android-custom-lint-rules/api-guide.html#writingalintcheck:basics/creatinganissue) section.