code: public ServerFilter where(Predicate<ServerMetadata> filter) {
          checkNotNull(filter, "Filter must be not a null");
  
          predicate = predicate.and(filter);
  
          return this;
      }
docs: Method allow to specify custom search servers predicate
  
  @param filter is not null custom filtering predicate
  @return {@link ServerFilter}
  @throws NullPointerException if {@code filter} is null