@Override
    public String toString() {
        return new StringJoiner(", ", ProbeContext.class.getSimpleName() + "[", "]")
                .add("apiKey='" + apiKey + "'")
                .add("contract=" + contract)
                .add("api=" + api)
                .add("url='" + url + "'")
                .toString();
    }
@author Marc Savy {@literal <marc@blackparrotlabs.io>}
gateway/engine/core/src/main/java/io/apiman/gateway/engine/policy/ProbeContext.java