src/vs/platform/extensionManagement/node/extensionManagementService.ts/ExtensionManagementService/isUninstalled
class ExtensionManagementService:	private async isUninstalled(identifier: ExtensionIdentifierWithVersion): Promise<boolean> {
		const uninstalled = await this.filterUninstalled(identifier);
		return uninstalled.length === 1;
	}