PresentationResult

public sealed class PresentationResult
{
    public bool Presented;                 // a sheet appeared
    public NotPresentedReason Reason;      // why not, when Presented is false
    public string ErrorType;               // the error, when there was one
    public string ErrorMessage;
    public AdvertiserOutcomeType Advertiser;
    public ClaimedOffer Offer;
    public string Publisher;
    public string Dismissal;               // how the sheet closed, such as "close_button"
    public ClaimedOffer Claim { get; }     // Offer when the player claimed, else null
}

public sealed class ClaimedOffer
{
    public string OfferId;                 // null on Android
    public string CampaignId;
    public string AdvertiserName;
    public string TransactionId;           // keep it: it carries the attribution
}

public enum AdvertiserOutcomeType { NotAttempted, Claimed, Verified, Cooldown, Failed, Unknown }

public enum NotPresentedReason
{
    None, NotConfigured, AlreadyPresenting, NoOffers, ExperimentControl, UseCaseUnavailable, Error,
    NoForegroundActivity,   // Android only
    IapFirstDeclined,       // Android only
    UnsupportedOS,          // iOS only
    Unknown,                // a value this package version does not know
}

if (result.Claim?.TransactionId is string transactionId) SaveClaim(transactionId);
else if (!result.Presented) Debug.Log($"No sheet: {result.Reason}");