As per @Rawi01's experimenting:

* VSCode's lombok plugin simply adds the appropriate `-javaagent` options when it fires up the eclipse-based language server. You can also add debug flags here.
* Add the flags `-agentlib:jdwp-transport=dt_socket,server=y,suspend=n,quiet=y,address=12345` to the `settings.json` of the VSCode lombok plugin, and then tell your debugger to attach to localhost:12345.
* Set the property `java.server.launchMode` to `"Standard"`.
* Consider activing the language server debug mode.