src/vs/workbench/services/extensions/common/abstractExtensionService.ts/AbstractExtensionService/_activateById
class AbstractExtensionService:	public async _activateById(extensionId: ExtensionIdentifier, reason: ExtensionActivationReason): Promise<void> {
		const results = await Promise.all(
			this._extensionHostManagers.map(manager => manager.activate(extensionId, reason))
		);
		const activated = results.some(e => e);
		if (!activated) {
			throw new Error(`Unknown extension ${extensionId.value}`);
		}
	}