src/vs/platform/markers/common/markerService.ts/MarkerService/_toMarker
class MarkerService:	private static _toMarker(owner: string, resource: URI, data: IMarkerData): IMarker | undefined {
		let {
			code, severity,
			message, source,
			startLineNumber, startColumn, endLineNumber, endColumn,
			relatedInformation,
			tags,
		} = data;

		if (!message) {
			return undefined;
		}

		// santize data
		startLineNumber = startLineNumber > 0 ? startLineNumber : 1;
		startColumn = startColumn > 0 ? startColumn : 1;
		endLineNumber = endLineNumber >= startLineNumber ? endLineNumber : startLineNumber;
		endColumn = endColumn > 0 ? endColumn : startColumn;

		return {
			resource,
			owner,
			code,
			severity,
			message,
			source,
			startLineNumber,
			startColumn,
			endLineNumber,
			endColumn,
			relatedInformation,
			tags,
		};
	}