@Override
    public String toString() {
        return new StringJoiner(", ", ApiPlanBeanCompositeId.class.getSimpleName() + "[", "]")
                .add("apiVersion=??")
                .add("planId='" + planId + "'")
                .add("version='" + version + "'")
                .toString();
    }
Composite ID for {@link ApiPlanBean}

@author Marc Savy {@literal <marc@blackparrotlabs.io>}
manager/api/beans/src/main/java/io/apiman/manager/api/beans/apis/ApiPlanBeanCompositeId.java