public Set<String> getReadOnlyProperties() {
        return getConstrainedProperties(definition -> {
            Set<CfnResourceIndex.Mutability> mutabilities = definition.getMutabilities();
            return mutabilities.size() == 1 && mutabilities.contains(CfnResourceIndex.Mutability.READ);
        });
    }
Get read-only property definitions of the CloudFormation resource.

These properties can be returned by a {@code read} or {@code list} request,
but cannot be set by the user.

@return Returns read-only member names that map to CloudFormation resource
  properties.
smithy-aws-cloudformation-traits/src/main/java/software/amazon/smithy/aws/cloudformation/traits/CfnResource.java