src/vs/workbench/services/extensions/common/extensionHostManager.ts/LazyStartExtensionHostManager/deltaExtensions
class LazyStartExtensionHostManager:	public async deltaExtensions(toAdd: IExtensionDescription[], toRemove: ExtensionIdentifier[]): Promise<void> {
		await this._startCalled.wait();
		const extensionHostAlreadyStarted = Boolean(this._actual);
		const shouldStartExtensionHost = (toAdd.length > 0);
		if (extensionHostAlreadyStarted || shouldStartExtensionHost) {
			const actual = await this._getOrCreateActualAndStart(`contains ${toAdd.length} new extension(s) (installed or enabled): ${toAdd.map(ext => ext.identifier.value)}`);
			return actual.deltaExtensions(toAdd, toRemove);
		}
	}