src/vs/workbench/contrib/tasks/common/problemMatcher.ts/MultiLineMatcher/next
class MultiLineMatcher:	public override next(line: string): IProblemMatch | null {
		const pattern = this.patterns[this.patterns.length - 1];
		Assert.ok(pattern.loop === true && this.data !== null);
		const matches = pattern.regexp.exec(line);
		if (!matches) {
			this.data = undefined;
			return null;
		}
		const data = Objects.deepClone(this.data);
		let problemMatch: IProblemMatch | undefined;
		if (this.fillProblemData(data, pattern, matches)) {
			problemMatch = this.getMarkerMatch(data);
		}
		return problemMatch ? problemMatch : null;
	}