src/vs/base/browser/ui/list/listWidget.ts/Trait/_set
class Trait:	private _set(indexes: number[], sortedIndexes: number[], browserEvent?: UIEvent): number[] {
		const result = this.indexes;
		const sortedResult = this.sortedIndexes;

		this.indexes = indexes;
		this.sortedIndexes = sortedIndexes;

		const toRender = disjunction(sortedResult, indexes);
		this.renderer.renderIndexes(toRender);

		this._onChange.fire({ indexes, browserEvent });
		return result;
	}