src/vs/workbench/contrib/output/common/outputChannelModel.ts/BufferedContent/getDelta
class BufferedContent:	public getDelta(previousId?: number): { value: string, id: number } {
		let idx = -1;
		if (previousId !== undefined) {
			idx = binarySearch(this.dataIds, previousId, (a, b) => a - b);
		}

		const id = this.idPool;
		if (idx >= 0) {
			const value = strings.removeAnsiEscapeCodes(this.data.slice(idx + 1).join(''));
			return { value, id };
		} else {
			const value = strings.removeAnsiEscapeCodes(this.data.join(''));
			return { value, id };
		}
	}