function PoolCluster(config) {
  EventEmitter.call(this);

  config = config || {};
  this._canRetry = typeof config.canRetry === 'undefined' ? true : config.canRetry;
  this._defaultSelector = config.defaultSelector || 'RR';
  this._removeNodeErrorCount = config.removeNodeErrorCount || 5;
  this._restoreNodeTimeout = config.restoreNodeTimeout || 0;

  this._closed = false;
  this._findCaches = Object.create(null);
  this._lastId = 0;
  this._namespaces = Object.create(null);
  this._nodes = Object.create(null);
}
PoolCluster
@constructor
@param {object} [config] The pool cluster configuration
@public