{
    updateClusters(config, settings, config_prefix);
}
ClusterPtr Clusters::getCluster(const std::string & cluster_name) const
{
    std::lock_guard lock(mutex);
    auto it = impl.find(cluster_name);
    return (it != impl.end()) ? it->second : nullptr;
}
void Clusters::setCluster(const String & cluster_name, const std::shared_ptr<Cluster> & cluster)
{
    std::lock_guard lock(mutex);
    impl[cluster_name] = cluster;
}
void Clusters::updateClusters(const Poco::Util::AbstractConfiguration & new_config, const Settings & settings, const String & config_prefix, Poco::Util::AbstractConfiguration * old_config)