src/vs/editor/browser/services/abstractCodeEditorService.ts/AbstractCodeEditorService/getModelProperty
class AbstractCodeEditorService:	public getModelProperty(resource: URI, key: string): any {
		const key1 = resource.toString();
		if (this._modelProperties.has(key1)) {
			const innerMap = this._modelProperties.get(key1)!;
			return innerMap.get(key);
		}
		return undefined;
	}