if (!timings.isEmpty()) {
                double avgTime = timings.stream().mapToLong(Long::longValue).average().orElse(0.0);
                long maxTime = timings.stream().mapToLong(Long::longValue).max().orElse(0L);
                long minTime = timings.stream().mapToLong(Long::longValue).min().orElse(0L);

                double variance = (maxTime - minTime) / avgTime;

            case LEAST_CONNECTIONS:
                return channels.stream()
                        .min((c1, c2) -> Integer.compare(c1.getActiveConnections(), c2.getActiveConnections()))
                        .orElse(channels.get(0));

            case RANDOM:
                return channels.get((int) (Math.random() * channels.size()));

            case FAILOVER_ONLY:
            default:

     *
     * @return The username, or "guest" if not logged in.
     */
    public String getUsername() {
        return getRequestManager().findUserBean(FessUserBean.class).map(FessUserBean::getUserId).orElse(Constants.GUEST_USER);
    }

    /**
     * Gets the request manager.
     *
     * @return The request manager.
     */
    protected RequestManager getRequestManager() {

                    }
                }
                return null;
            }

            return new ActionResponseCredential(() -> HtmlResponse.fromRedirectPathAsIs(getAuthUrl(request)));
        }).orElse(null);
    }

    /**
     * Generates the Azure AD authorization URL for the authentication request.
     * @param request The HTTP servlet request.
     * @return The authorization URL to redirect the user to.