src/vs/workbench/api/common/extHostEditorTabs.ts/ExtHostEditorTabs/_closeTabs
class ExtHostEditorTabs:	private async _closeTabs(tabs: vscode.Tab[], preserveFocus?: boolean): Promise<boolean> {
		const extHostTabIds: string[] = [];
		for (const tab of tabs) {
			const extHostTab = this._findExtHostTabFromApi(tab);
			if (!extHostTab) {
				throw new Error('Tab close: Invalid tab not found!');
			}
			extHostTabIds.push(extHostTab.tabId);
		}
		return this._proxy.$closeTab(extHostTabIds, preserveFocus);
	}