It is correct to record RequestOptions for cancelToken

[Rofl113]

In the method, when RequestOptions is formed, compose is called, and then copyWith, and that's the problem.
A cancelToken is attached to RequestOptions in compose.
When calling copyWith, a new RequestOptions is created, but the old cancelToken is passed, which is linked to the RequestOptions itself.
Because of this, when canceling via CancelToken, we will not get the working RequestOptions, but rather the initial RequestOptions, which will contain almost nothing.
In order to avoid this, you need to add a line before calling the fetch function.

cancelToken.requestOptions = _options;
final _result = await _dio.fetch<Map<String, dynamic>>(_options);