type uaTransport struct {
	ua string
	rt http.RoundTripper
}

func (u *uaTransport) RoundTrip(req *http.Request) (*http.Response, error) {
	req2 := req.Clone(req.Context())
	req2.Header.Set("User-Agent", u.ua)
	return u.rt.RoundTrip(req2)
}

// WithUserAgent wraps an existing transport with custom User-Agent
func WithUserAgent(rt http.RoundTripper, getUA func() string) http.RoundTripper {
	return &uaTransport{
		ua: getUA(),

)

const defaultFlushInterval = time.Duration(100) * time.Millisecond

// Forwarder forwards all incoming HTTP requests to configured transport.
type Forwarder struct {
	RoundTripper http.RoundTripper
	PassHost     bool
	Logger       func(error)
	ErrorHandler func(http.ResponseWriter, *http.Request, error)

	// internal variables
	rewriter *headerRewriter
}

// convenient wrapper to drain any remaining data on response body.
//
// Subsequently this allows golang http RoundTripper
// to reuse the same connection for future requests.
func DrainBody(respBody io.ReadCloser) {
	// Callers should close resp.Body when done reading from it.
	// If resp.Body is not closed, the Client's underlying RoundTripper
	// (typically Transport) may not be able to reuse a persistent TCP

}

// RoundTripper provides an interface for type roundtrip serialization.
type RoundTripper interface {
	msgp.Unmarshaler
	msgp.Marshaler
	msgp.Sizer

	comparable
}

// SingleHandler is a type safe handler for single roundtrip requests.
type SingleHandler[Req, Resp RoundTripper] struct {
	id            HandlerID
	sharedResp    bool

// initializeProvider initializes if any additional vendor specific information
// was provided, initialization will return an error initial login fails.
func (p *providerCfg) initializeProvider(cfgGet func(string) string, transport http.RoundTripper) error {
	vendor := cfgGet(Vendor)
	if vendor == "" {
		return nil
	}
	var err error
	switch vendor {
	case keyCloakVendor:
		adminURL := cfgGet(KeyCloakAdminURL)
		realm := cfgGet(KeyCloakRealm)

	APIKey string `json:"apiKey"`

	// The HTTP(S) proxy URL to use for connecting to SUBNET
	Proxy string `json:"proxy"`

	// Transport configured with proxy_url if set optionally.
	transport http.RoundTripper

	// The subnet base URL
	BaseURL string
}

var configLock sync.RWMutex

// Registered indicates if cluster is registered or not
func (c *Config) Registered() bool {
	configLock.RLock()

func (NoPayload) Recycle() {}

// ArrayOf wraps an array of Messagepack compatible objects.
type ArrayOf[T RoundTripper] struct {
	aPool sync.Pool     // Arrays
	ePool bpool.Pool[T] // Elements
}

// NewArrayOf returns a new ArrayOf.
// You must provide a function that returns a new instance of T.
func NewArrayOf[T RoundTripper](newFn func() T) *ArrayOf[T] {
	return &ArrayOf[T]{
		ePool: bpool.Pool[T]{New: func() T {

}

// Option is a function type that accepts a pointer Target
type Option func(*KeycloakProvider)

// WithTransport provide custom transport
func WithTransport(transport http.RoundTripper) Option {
	return func(p *KeycloakProvider) {
		p.client = http.Client{
			Transport: transport,
		}
	}
}

// WithOpenIDConfig provide OpenID Endpoint configuration discovery document

	globalMRFState = newMRFState()

	// If writes to FS backend should be O_SYNC.
	globalFSOSync bool

	globalProxyEndpoints []ProxyEndpoint

	globalInternodeTransport http.RoundTripper

	globalRemoteTargetTransport http.RoundTripper

	globalDNSCache = &dnscache.Resolver{
		Timeout: 5 * time.Second,
	}

	globalForwarder *handlers.Forwarder

	globalTierConfigMgr *TierConfigMgr

		},
	}
)

// Args opa general purpose policy engine configuration.
type Args struct {
	URL         *xnet.URL             `json:"url"`
	AuthToken   string                `json:"authToken"`
	Transport   http.RoundTripper     `json:"-"`
	CloseRespFn func(r io.ReadCloser) `json:"-"`
}

// Validate - validate opa configuration params.
func (a *Args) Validate() error {