src/vs/editor/common/model/pieceTreeTextBuffer/pieceTreeBase.ts/PieceTreeBase/getContentOfSubTree
class PieceTreeBase:	private getContentOfSubTree(node: TreeNode): string {
		let str = '';

		this.iterate(node, node => {
			str += this.getNodeContent(node);
			return true;
		});

		return str;
	}