code: public PooledExecutionServiceConfigurationBuilder pool(String alias, int minSize, int maxSize) {
      PooledExecutionServiceConfigurationBuilder other = new PooledExecutionServiceConfigurationBuilder(this);
      other.pools.add(new Pool(alias, minSize, maxSize));
      return other;
    }
docs: Adds a pool configuration to the returned builder.
  
  @param alias the pool alias
  @param minSize the minimum number of threads in the pool
  @param maxSize the maximum number of threads in the pool
  @return a new builder with the added default pool