extensions/typescript-language-features/src/tsServer/bufferSyncSupport.ts/TabResourceTracker/add
class TabResourceTracker:	private add(tab: vscode.Tab): vscode.Uri[] {
		const addedResources: vscode.Uri[] = [];
		for (const uri of this.getResourcesForTab(tab)) {
			const entry = this._tabResources.get(uri);
			if (entry) {
				entry.tabs.add(tab);
			} else {
				this._tabResources.set(uri, { tabs: new Set([tab]) });
				addedResources.push(uri);
			}
		}
		return addedResources;
	}