@Override
        public String toString() {
            return "Key{" +
                    "userRef='" + userRef + '\'' +
                    ", queryId='" + queryId + '\'' +
                    '}';
        }
Registers a query as in progress and holds its taskid
stroom-meta/stroom-meta-impl/src/main/java/stroom/meta/impl/UserQueryRegistry.java