src/vs/workbench/api/common/extHostLanguageFeatures.ts/ReferenceAdapter/provideReferences
class ReferenceAdapter:	async provideReferences(resource: URI, position: IPosition, context: languages.ReferenceContext, token: CancellationToken): Promise<languages.Location[] | undefined> {
		const doc = this._documents.getDocument(resource);
		const pos = typeConvert.Position.to(position);

		const value = await this._provider.provideReferences(doc, pos, context, token);
		if (Array.isArray(value)) {
			return value.map(typeConvert.location.from);
		}
		return undefined;
	}