The server handler function has this signature: `type SingleHandlerFn func(payload []byte) ([]byte, *RemoteErr)`.

Sample handler:
```go
    handler :=  func(payload []byte) ([]byte, *grid.RemoteErr) {
        // Do something with payload
        return []byte("response"), nil
    }

    err := manager.RegisterSingleHandler(grid.HandlerDiskInfo, handler)
```

	if errCode != ErrNone {
		return cred, "", "", time.Time{}, errCode
	}

	// Payload streaming.
	payload := streamingContentSHA256
	if trailers {
		payload = streamingContentSHA256Trailer
	}

	// Payload for STREAMING signature should be 'STREAMING-AWS4-HMAC-SHA256-PAYLOAD'
	if payload != req.Header.Get(xhttp.AmzContentSha256) {
		return cred, "", "", time.Time{}, ErrContentSHA256Mismatch
	}

    assert response.json() == {"detail": "Not authenticated"}


def test_security_http_basic_non_basic_credentials():
    payload = b64encode(b"johnsecret").decode("ascii")
    auth_header = f"Basic {payload}"
    response = client.get("/users/me", headers={"Authorization": auth_header})
    assert response.status_code == 401, response.text

		return
	}

	// Route directly to output.
	m.respWait = out
}

// RequestStream will send a single payload request and stream back results.
// 'requests' can be nil, in which case only req is sent as input.
// It will however take less resources.
func (m *muxClient) RequestStream(h HandlerID, payload []byte, requests chan []byte, responses chan Response) (*Stream, error) {
	if m.init {

// The remaining payload and versions are returned.
func checkXL2V1(buf []byte) (payload []byte, major, minor uint16, e error) {
	if len(buf) <= 8 {
		return payload, 0, 0, fmt.Errorf("xlMeta: no data")
	}

	if !bytes.Equal(buf[:4], xlHeader[:]) {
		return payload, 0, 0, fmt.Errorf("xlMeta: unknown XLv2 header, expected %v, got %v", xlHeader[:4], buf[:4])
	}

        headers={"WWW-Authenticate": authenticate_value},
    )
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        username: str = payload.get("sub")
        if username is None:
            raise credentials_exception
        scope: str = payload.get("scope", "")
        token_scopes = scope.split(" ")

    assert response.json() == {"detail": "Not authenticated"}


def test_security_http_basic_non_basic_credentials(client: TestClient):
    payload = b64encode(b"johnsecret").decode("ascii")
    auth_header = f"Basic {payload}"
    response = client.get("/users/me", headers={"Authorization": auth_header})
    assert response.status_code == 401, response.text

    assert response.headers["WWW-Authenticate"] == "Basic"
    assert response.json() == {"detail": "Not authenticated"}


def test_security_http_basic_non_basic_credentials():
    payload = b64encode(b"johnsecret").decode("ascii")
    auth_header = f"Basic {payload}"
    response = client.get("/users/me", headers={"Authorization": auth_header})
    assert response.status_code == 401, response.text

        headers={"WWW-Authenticate": authenticate_value},
    )
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        username: str = payload.get("sub")
        if username is None:
            raise credentials_exception
        scope: str = payload.get("scope", "")
        token_scopes = scope.split(" ")

        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
        headers={"WWW-Authenticate": "Bearer"},
    )
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        username = payload.get("sub")
        if username is None:
            raise credentials_exception
        token_data = TokenData(username=username)
    except InvalidTokenError: