src/vs/workbench/contrib/welcome/gettingStarted/browser/gettingStartedService.ts/GettingStartedService/registerCompletionListener
class GettingStartedService:	private registerCompletionListener(event: string, step: IGettingStartedStep) {
		if (!this.completionListeners.has(event)) {
			this.completionListeners.set(event, new Set());
		}
		this.completionListeners.get(event)?.add(step.id);
	}