public WorkerPipeline<O> sinkToConsumer(String name, int threads, Consumer<O> consumer) {
      return sinkTo(name, threads, (prev) -> {
        for (O item : prev) {
          consumer.accept(item);
        }
      });
    }
Runs {@code threads} simultaneous worker threads that consume items from previous step and invoke {@code
consumer.accept} for each one.
planetiler-core/src/main/java/com/onthegomap/planetiler/worker/WorkerPipeline.java