src/vs/editor/contrib/folding/browser/syntaxRangeProvider.ts/RangesCollector/add
class RangesCollector:	public add(startLineNumber: number, endLineNumber: number, type: string | undefined, nestingLevel: number) {
		if (startLineNumber > MAX_LINE_NUMBER || endLineNumber > MAX_LINE_NUMBER) {
			return;
		}
		const index = this._length;
		this._startIndexes[index] = startLineNumber;
		this._endIndexes[index] = endLineNumber;
		this._nestingLevels[index] = nestingLevel;
		this._types[index] = type;
		this._length++;
		if (nestingLevel < 30) {
			this._nestingLevelCounts[nestingLevel] = (this._nestingLevelCounts[nestingLevel] || 0) + 1;
		}
	}