TokenEndpointAuthMethods         []string `json:"token_endpoint_auth_methods_supported,omitempty"`
	ClaimsSupported                  []string `json:"claims_supported,omitempty"`
	CodeChallengeMethodsSupported    []string `json:"code_challenge_methods_supported,omitempty"`
}

func parseDiscoveryDoc(u *xnet.URL, transport http.RoundTripper, closeRespFn func(io.ReadCloser)) (DiscoveryDoc, error) {
	d := DiscoveryDoc{}