@Override public String toString() {
        return new StringJoiner(", ", RateLimitingProbeConfig.class.getSimpleName() + "[", "]")
                .add("user='" + user + "'")
                .add("apiKey='" + apiKey + "'")
                .add("callerIp='" + callerIp + "'")
                .toString();
    }
@author Marc Savy {@literal <marc@blackparrotlabs.io>}
gateway/engine/policies/src/main/java/io/apiman/gateway/engine/policies/probe/RateLimitingProbeConfig.java