@Override
    public String toString() {
        return new StringJoiner(", ", NewUserEventProcessor.class.getSimpleName() + "[", "]")
             .toString();
    }
Process a {@link org.keycloak.events.EventType#REGISTER} and send to Apiman Manager API via HTTP.
sso/keycloak/extensions/src/main/java/io/apiman/manager/sso/keycloak/event/processors/NewUserEventProcessor.java