How can I add AWS identity pool credentials to my API calls?

Description

Hello,

I am using the dart-dio-next generator on a Flutter project, and for the moment it's been working great. My aws API is protected by a user pool, so I add an Authorization header to all requests like so :

final response = await api.getShop(shopId: shopId, headers: {
  'Authorization': 'Bearer $TOKEN', // user pool token added here, works great
});

However, I now want to exchange my user pool token for Identity pool credentials, and use those instead to authenticate (as described here). The problem is that I'm not sure how to pass those to the request. Getting the credentials works fine, like so :

final credentials = CognitoCredentials('eu-west-3:5d943g9f-caa3-12bb-6fe1-92119691dc91', _userPool);

await credentials.getAwsCredentials(_session!.getIdToken().getJwtToken());
print(credentials.userIdentityId); // eu-west-3:b0eb9b78-a027-4882-9ef6-c37f7633b280

print(credentials.accessKeyId);
// ASIAZQBXPWO5M5YL6YNQ

print(credentials.secretAccessKey);
// Z48bwq2KC+ChzIGjzaFjUHJ29RkecLaVkd1Ms2yY

print(credentials.sessionToken);
// 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

As I said, auth with the user pool token works fine, but now I need to use an Identity Pool to retrieve correct IAM Role & permissions, and from my understanding I need to somehow use the accessKeyId, secretAccessKey and sessionToken that my identity pool is returning in my API calls.

Thanks in advance for any help!

Command line used for generation

npx @openapitools/openapi-generator-cli generate -i $open_api_file -g dart-dio-next -o dist/$sdk_name/

Start with the dart-dio-next generator and the generated API client, then compare the requested credential flow with the linked AWS Cognito authentication documentation. Determine whether credential injection requires a generator change or documentation; done means a clear, reproducible path for authenticated API calls.