@Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        selectionToString(sb, nodes);
        if ( ! groups.isEmpty()) {
            sb.append('/');
            selectionToString(sb, groups);
        }
        return sb.toString();
    }
A subset of nodes and groups to which a query should be sent.
See https://docs.vespa.ai/en/reference/query-api-reference.html#model.searchpath

@author ollivir
container-search/src/main/java/com/yahoo/search/dispatch/SearchPath.java