src/vs/workbench/contrib/extensions/browser/extensionsActions.ts/AbstractInstallAction/getRunningExtension
class AbstractInstallAction:	private async getRunningExtension(extension: ILocalExtension): Promise<IExtensionDescription | null> {
		const runningExtension = await this.runtimeExtensionService.getExtension(extension.identifier.id);
		if (runningExtension) {
			return runningExtension;
		}
		if (this.runtimeExtensionService.canAddExtension(toExtensionDescription(extension))) {
			return new Promise<IExtensionDescription | null>((c, e) => {
				const disposable = this.runtimeExtensionService.onDidChangeExtensions(async () => {
					const runningExtension = await this.runtimeExtensionService.getExtension(extension.identifier.id);
					if (runningExtension) {
						disposable.dispose();
						c(runningExtension);
					}
				});
			});
		}
		return null;
	}