src/vs/platform/extensionManagement/node/extensionsWatcher.ts/ExtensionsWatcher/addExtensionWithKey
class ExtensionsWatcher:	private addExtensionWithKey(key: string, extensionsProfileLocation: URI): void {
		let profiles = this.allExtensions.get(key);
		if (!profiles) {
			this.allExtensions.set(key, profiles = new ResourceSet((uri) => this.uriIdentityService.extUri.getComparisonKey(uri)));
		}
		profiles.add(extensionsProfileLocation);
	}