code: public CoordinatorConfig setBootstrapURLs(List<String> bootstrapUrls) {
          this.bootstrapURLs = Utils.notNull(bootstrapUrls);
          if(this.bootstrapURLs.size() <= 0)
              throw new IllegalArgumentException("Must provide at least one bootstrap URL.");
          return this;
      }
docs: Sets the bootstrap URLs used by the different Fat clients inside the
  Coordinator
  
  @param bootstrapUrls list of bootstrap URLs defining which cluster to
  connect to
  @return modified CoordinatorConfig