public static StroomStatusCode fromHttpCode(int httpCode) {
        return httpCode == OK.httpCode
                ? OK
                : UNKNOWN_ERROR;
    }
Should ONLY be used when a stroom status code is not known.

@return Either {@link StroomStatusCode#OK} if httpCode is 200 else
{@link StroomStatusCode#UNKNOWN_ERROR}
stroom-proxy/stroom-proxy-remote-api/src/main/java/stroom/proxy/StroomStatusCode.java