public void setWorking(boolean working) {
        this.statusIsKnown = true;
        this.working = working;
        if ( ! working ) {
            activeDocuments = 0;
            targetActiveDocuments = 0;
        }
    }
Returns the index of the group this node belongs to.
This is a 0-base continuous integer id, not necessarily the same as the group id assigned by the
application/node repo.
container-search/src/main/java/com/yahoo/search/dispatch/searchcluster/Node.java