Request to support IBM IAM API key based authentication

rclone is supporting IBM COS as one of the S3 providers.
But there is no option to use IBM IAM API key for authentication as AWS SDK does not support IBM IAM authentication mechanism.

We want to discuss the best approach to achieve the feature mentioned above.
We have the issue opened here.

My observation:
After going through the code, I can see that there are two ways to support a cloud provider

  1. A new backend
  2. Onboard as one of the S3 providers (Which how IBM COS is supported today).

As of now, I could not find a way to support the IBM IAM authentication mechanism through S3 provider way. However, I understand, if we write a new backend, we have all the flexibility to add our own authentication mechanism (IBM IAM service).

I want to discuss and get the best way to achieve this feature.