Subscription timeline API records primary key

[PTalend]

Hi, I am using the subscription email timeline API  to fetch the records. We are considering a set of the recipient, portalId, timestamp as the primary key. But, still, we have found that it is not a valid primary key. So, is there any specific set of keys by which we can uniquely identify records for subscription timeline records?

Thanks

[PKhokhani]

@dennisedson @himanshurauthan We are blocked due to the above issue. Can you please reply to us?

[dennisedson]

@himanshurauthan ,

Any chance you could assist here?