@Override
    public String getOriginalHost() {
        try {
            if (originalHost == null) {
                originalHost = getOriginalHost(getHeaders(), getServerName());
            }
            return originalHost;
        } catch (URISyntaxException e) {
            throw new IllegalArgumentException(e);
        }
    }
The originally request host. This will NOT include port.

The Host header may contain port, but in this method we strip it out for consistency - use the
getOriginalPort method for that.
zuul-core/src/main/java/com/netflix/zuul/message/http/HttpRequestMessageImpl.java