Certificate Pinning / OktaOidc

We are using OKTA Open Id Connect Library (OktaOidc SDK) in your IPAD application (developed in Swift) to handle OKTA authorization process. We want to implement certificate pinning to prevent MITM attack. Are there specific APIs to use in OktaOidc SDK or do we have to manage through URLSession ?
We didn’t see anything relative to certificate pinning in OktaOidc SDK.