src/vs/base/browser/ui/list/listWidget.ts/TraitRenderer/splice
class TraitRenderer:	splice(start: number, deleteCount: number, insertCount: number): void {
		const rendered: IRenderedContainer[] = [];

		for (const renderedElement of this.renderedElements) {

			if (renderedElement.index < start) {
				rendered.push(renderedElement);
			} else if (renderedElement.index >= start + deleteCount) {
				rendered.push({
					index: renderedElement.index + insertCount - deleteCount,
					templateData: renderedElement.templateData
				});
			}
		}

		this.renderedElements = rendered;
	}