src/vs/editor/contrib/folding/foldingRanges.ts/FoldingRegions/constructor
class FoldingRegions:	constructor(startIndexes: Uint32Array, endIndexes: Uint32Array, types?: Array<string | undefined>) {
		if (startIndexes.length !== endIndexes.length || startIndexes.length > MAX_FOLDING_REGIONS) {
			throw new Error('invalid startIndexes or endIndexes size');
		}
		this._startIndexes = startIndexes;
		this._endIndexes = endIndexes;
		this._collapseStates = new Uint32Array(Math.ceil(startIndexes.length / 32));
		this._types = types;
		this._parentsComputed = false;
	}