有没有办法将flutter包转换为插件？

Question

I have a Package made a while ago but I want to add some Android specific code (Java, but this doesn't matter). The only approach I currently have is just creating a new Plugin and moving things around from the old package to the new plugin.

Is there another way I'm missing? Maybe a command line prompt or another tool?

Note for the differences between Package and Plugin from flutter.dev