src/vs/platform/extensionManagement/common/abstractExtensionManagementService.ts/AbstractExtensionTask/run
class AbstractExtensionTask:	async run(): Promise<T> {
		if (!this.cancellablePromise) {
			this.cancellablePromise = createCancelablePromise(token => this.doRun(token));
		}
		this.barrier.open();
		return this.cancellablePromise;
	}