in src/shippers/fullstory/src/fullstory_shipper.ts [179:187]
public extendContext(newContext: EventContext): void {
this.initContext.logger.debug(() => `Received context ${JSON.stringify(newContext)}`);
// FullStory requires different APIs for different type of contexts:
// User-level context.
this.userContext$.next(newContext);
// Event-level context. At the moment, only the scope `page` is supported by FullStory for webapps.
this.pageContext$.next(newContext);
}