@Override
    public boolean equals(Object o) {
        if (o == this) return true;
        if ( ! (o instanceof Node other)) return false;
        if ( ! Objects.equals(this.hostname, other.hostname)) return false;
        if ( ! Objects.equals(this.key, other.key)) return false;
        if ( ! Objects.equals(this.group, other.group)) return false;

        return true;
    }
Returns the active documents on this node. If unknown, 0 is returned.
container-search/src/main/java/com/yahoo/search/dispatch/searchcluster/Node.java