this.outputDirectories = fileCollectionFactory.configurableFiles(sourceSetDisplayName + " classes");
        outputDirectories.from(classesDirs, (Callable<File>) this::getResourcesDir);

        this.dirs = fileCollectionFactory.configurableFiles(sourceSetDisplayName + " dirs");

        this.generatedSourcesDirs = fileCollectionFactory.configurableFiles(sourceSetDisplayName + " generatedSourcesDirs");

 *   main {
 *     output.dir(generateResourcesTask)
 *   }
 * }
 *
 * abstract class GenerateResourcesTask extends DefaultTask {
 *   {@literal @}OutputDirectory
 *   abstract DirectoryProperty getResourcesDir()
 *
 *   {@literal @}TaskAction
 *   def generateResources() {
 *     def generated = resourcesDir.file("myGeneratedResource.properties").get().asFile
 *     generated.text = "message=Stay happy!"
 *   }
 * }