src/vs/editor/common/textModelEvents.ts/ModelRawContentChangedEvent/merge
class ModelRawContentChangedEvent:	public static merge(a: ModelRawContentChangedEvent, b: ModelRawContentChangedEvent): ModelRawContentChangedEvent {
		const changes = ([] as ModelRawChange[]).concat(a.changes).concat(b.changes);
		const versionId = b.versionId;
		const isUndoing = (a.isUndoing || b.isUndoing);
		const isRedoing = (a.isRedoing || b.isRedoing);
		return new ModelRawContentChangedEvent(changes, versionId, isUndoing, isRedoing);
	}