@Override
    public NodeConnection getConnection(int nodeId) {
        var pool = nodeConnectionPools.get(nodeId);
        if (pool == null) {
            return null;
        } else {
            return pool.nextConnection();
        }
    }
Connections to the search nodes this talks to, indexed by node id ("partid")
container-search/src/main/java/com/yahoo/search/dispatch/rpc/RpcResourcePool.java