code: public void setArbitrationStrategy(ArbitrationStrategy arbitrationStrategy) {
          if (arbitrationStrategy.equals(ArbitrationStrategy.Custom)) {
              throw new IllegalStateException("A Custom strategy can only be set by passing an arbitration strategy function to the DiscoveryQos constructor");
          }
          this.arbitrationStrategy = arbitrationStrategy;
      }
docs: The discovery process outputs a list of matching providers. The arbitration strategy then chooses one or more of
  them to be used by the proxy.
  
  @param arbitrationStrategy
  Defines the strategy used to choose the "best" provider.