Cannot add values to dio data inside interceptor

[centralizer]

Package

dio

Version

5.2.1+1

Operating-System

iOS

Output of flutter doctor -v

No response

Dart Version

No response

Steps to Reproduce

I am attempting to add a value channelId to the data object inside the interceptor. I have tried everything and cannot get this to work. The first if check adds the value to requests that do not have a data object. That works fine. The second if check is supposed to add the value to existing data objects and I cannot get this to work. I have included screenshots of the data print and runtimeType result, including error. I really would appreciate some help. This really seems like something that should be trivial.

  void onRequest(RequestOptions options, RequestInterceptorHandler handler) {
    final role = storage.readRole();

    if (role?.id != null && options.data == null) {
      options.data = {"channelId": role?.id};
    }

    if (role?.id != null && options.data != null) {
      options.data["channelId"] = role?.id;
    }

    return super.onRequest(options, handler);
  }

Expected Result

The channelId key/value would be added to the data object.

Actual Result

Resulting error.

[AlexV525]

Tests in https://github.com/cfug/dio/blob/main/dio/test/interceptor_test.dart are all running well. Perhaps you didn't add the interceptor to your instance or the data was renormalized by another interceptor?