src/vs/workbench/api/common/extHostExtensionService.ts/AbstractExtHostExtensionService/$deltaExtensions
class AbstractExtHostExtensionService:	public async $deltaExtensions(extensionsDelta: IExtensionDescriptionDelta): Promise<void> {
		extensionsDelta.toAdd.forEach((extension) => (<any>extension).extensionLocation = URI.revive(extension.extensionLocation));

		// First build up and update the trie and only afterwards apply the delta
		const { globalRegistry, myExtensions } = AbstractExtHostExtensionService._applyExtensionsDelta(this._globalRegistry, this._myRegistry, extensionsDelta);
		const newSearchTree = await this._createExtensionPathIndex(myExtensions);
		const extensionsPaths = await this.getExtensionPathIndex();
		extensionsPaths.setSearchTree(newSearchTree);
		this._globalRegistry.set(globalRegistry.getAllExtensionDescriptions());
		this._myRegistry.set(myExtensions);

		return Promise.resolve(undefined);
	}