private static OAuth2AccessTokenResponse getFreshToken(OAuth2AuthorizedClient expiredClient) {
    OAuth2RefreshTokenGrantRequest refreshRequest = new OAuth2RefreshTokenGrantRequest(
        expiredClient.getClientRegistration(),
        expiredClient.getAccessToken(),
        expiredClient.getRefreshToken());

    return new DefaultRefreshTokenTokenResponseClient()
        .getTokenResponse(refreshRequest);
  }
Refreshes the expired client's access token, reconnects the associated user's cluster using
the new token, and returns the reconnected cluster. If the access token cannot be refreshed,
the user's cluster is disconnected from JMX and removed from the repository.
geode-pulse/src/main/java/org/apache/geode/tools/pulse/internal/data/Repository.java