public BloxClientBuilder iamRegion(String iamRegion) {
        setIamRegion(iamRegion);
        return this;
    }
Sets the IAM region to use when using IAM auth'd requests against a service in any of it's non-default regions.
This is only expected to be used when a custom endpoint has also been set.

@param iamRegion
       the IAM region string to use when signing
@return This object for method chaining.
frontend-service-client/src/main/java/com/amazonaws/blox/BloxClientBuilder.java