docs: public OAuth2AccessToken refreshAccessToken(OAuth2ProtectedResourceDetails resource,
  			OAuth2RefreshToken refreshToken, AccessTokenRequest request)
  			throws UserRedirectRequiredException {
  		for (AccessTokenProvider tokenProvider : chain) {
  			if (tokenProvider.supportsRefresh(resource)) {
  				DefaultOAuth2AccessToken refreshedAccessToken = new DefaultOAuth2AccessToken(
  						tokenProvider.refreshAccessToken(resource, refreshToken,
  								request));
  				if (refreshedAccessToken.getRefreshToken() == null) {
  					// Fixes gh-712
  					refreshedAccessToken.setRefreshToken(refreshToken);
  				}
  				return refreshedAccessToken;
  			}
  		}
  		throw new OAuth2AccessDeniedException(
  				"Unable to obtain a new access token for resource '" + resource.getId()
  						+ "'. The provider manager is not configured to support it.",
  				resource);
  	}