How can we distinguish beteen webpack.compiler and Rspack.compiler?

[GiveMe-A-Name]

As we known, the Rspack is progressively aligning webpack plugin api.
Sometimes, We want to write a custom plugin that not only support rspack but also support Webpack.
In some situations, we custom logic for rspack & webpack, like this:

apply(compiler) {
  if(isRspack) {
    // doSomethingWithRspack
  } else if(isWebpack) {
    // doSomethingWithWebpack
  }
}

So in the plugin we need distinguish the bundler.
We observed the Rspack.compiler.webpack has a rspackVersion attribute, but we think it's not a good way to distinguish beteen them. Rspack.compiler.webpack.rspackVersion maybe a unstable field.
So what is a good way to distinguish them?

[h-a-n-a]

rspackVersion is supposed to be a stable field with different version for each release. So I will recommend to use this field.