src/vs/workbench/contrib/notebook/common/services/notebookSimpleWorker.ts/MirrorCell/textBuffer
class MirrorCell:	get textBuffer() {
		if (this._textBuffer) {
			return this._textBuffer;
		}

		const builder = new PieceTreeTextBufferBuilder();
		builder.acceptChunk(Array.isArray(this._source) ? this._source.join('\n') : this._source);
		const bufferFactory = builder.finish(true);
		this._textBuffer = bufferFactory.create(model.DefaultEndOfLine.LF).textBuffer;

		return this._textBuffer;
	}