Reducing the number of threads created by the ElasticSearch Transport Client

This is a quick snippet saved for posterity so that I won't have to pull my hair out the next time I run into this issue. To reduce the number of threads spawned by the ElasticSearch transport client (default is 2 x num_cores) add the following option to the settings object:

Settings settings = ImmutableSettings.settingsBuilder().put("transport.netty.workerCount",NUM_THREADS).build();