builder.setBolt("fetch", new FetcherBolt()).fieldsGrouping(
"partitioner", new Fields("key"));
builder.setBolt("parse", new ParserBolt()).shuffleGrouping("fetch");
builder.setBolt("index", new IndexerBolt()).shuffleGrouping("parse");
conf.registerMetricsConsumer(DebugMetricConsumer.class);
return submit("crawl", conf, builder);
}