private async Task <string> SerializeRefreshTokenAsync(
            ClaimsPrincipal principal, AuthenticationProperties properties,
            OpenIdConnectRequest request, OpenIdConnectResponse response)
        {
            // Note: claims in refresh tokens are never filtered as they are supposed to be opaque:
            // SerializeAccessTokenAsync and SerializeIdentityTokenAsync are responsible of ensuring
            // that subsequent access and identity tokens are correctly filtered.

            // Create a new ticket containing the updated properties.
            var ticket = new AuthenticationTicket(principal, properties, Scheme.Name);

            ticket.Properties.IssuedUtc = Options.SystemClock.UtcNow;

            // Only set the expiration date if a lifetime was specified in either the ticket or the options.
            var lifetime = ticket.GetRefreshTokenLifetime() ?? Options.RefreshTokenLifetime;

            if (lifetime.HasValue)
            {
                ticket.Properties.ExpiresUtc = ticket.Properties.IssuedUtc + lifetime.Value;
            }

            // Associate a random identifier with the refresh token.
            ticket.SetTokenId(Guid.NewGuid().ToString());

            // Remove the unwanted properties from the authentication ticket.
            ticket.RemoveProperty(OpenIdConnectConstants.Properties.AuthorizationCodeLifetime)
            .RemoveProperty(OpenIdConnectConstants.Properties.CodeChallenge)
            .RemoveProperty(OpenIdConnectConstants.Properties.CodeChallengeMethod)
            .RemoveProperty(OpenIdConnectConstants.Properties.Nonce)
            .RemoveProperty(OpenIdConnectConstants.Properties.OriginalRedirectUri)
            .RemoveProperty(OpenIdConnectConstants.Properties.TokenUsage);

            var notification = new SerializeRefreshTokenContext(Context, Scheme, Options, request, response, ticket)
            {
                DataFormat = Options.RefreshTokenFormat
            };

            await Provider.SerializeRefreshToken(notification);

            if (notification.IsHandled || !string.IsNullOrEmpty(notification.RefreshToken))
            {
                return(notification.RefreshToken);
            }

            if (notification.DataFormat == null)
            {
                throw new InvalidOperationException("A data formatter must be provided.");
            }

            var result = notification.DataFormat.Protect(ticket);

            Logger.LogTrace("A new refresh token was successfully generated using the " +
                            "specified data format: {Token} ; {Claims} ; {Properties}.",
                            result, ticket.Principal.Claims, ticket.Properties.Items);

            return(result);
        }
 /// <summary>
 /// Represents an event called when serializing a refresh token.
 /// </summary>
 /// <param name="context">The context instance associated with this event.</param>
 /// <returns>A <see cref="Task"/> that can be used to monitor the asynchronous operation.</returns>
 public virtual Task SerializeRefreshToken(SerializeRefreshTokenContext context)
 => OnSerializeRefreshToken(context);