src/vs/editor/common/tokens/sparseMultilineTokens.ts/SparseMultilineTokensStorage/toString
class SparseMultilineTokensStorage:	public toString(startLineNumber: number): string {
		const pieces: string[] = [];
		for (let i = 0; i < this._tokenCount; i++) {
			pieces.push(`(${this._getDeltaLine(i) + startLineNumber},${this._getStartCharacter(i)}-${this._getEndCharacter(i)})`);
		}
		return `[${pieces.join(',')}]`;
	}