@Override
    public String toString() {
        return "{"
               + (hosts.isEmpty() ? "" : "hosts=" + hosts)
               + (srvHost == null ? "" : ", srvHost=" + srvHost)
               + (srvServiceName == null ? "" : ", srvServiceName=" + srvServiceName)
               + (srvMaxHosts == null ? "" : ", srvMaxHosts=" + srvMaxHosts)
               + ", mode=" + mode
               + ", requiredClusterType=" + requiredClusterType
               + ", requiredReplicaSetName='" + requiredReplicaSetName + '\''
               + ", serverSelector='" + serverSelector + '\''
               + ", clusterListeners='" + clusterListeners + '\''
               + ", serverSelectionTimeout='" + serverSelectionTimeoutMS + " ms" + '\''
               + ", localThreshold='" + serverSelectionTimeoutMS + " ms" + '\''
               + '}';
    }