If this is set to true, this means that a bolt will ack a tuple as soon as it is received and processing begins; otherwise, the tuple will be acked when the bolt completes.
If true, the topology will anchor tuples in all flatMap bolts and ack in the final sink bolt.
When a bolt is prepared, these metrics will be use by being called with the TopologyContext for the storm bolt.
This signals that the storm bolts should use localOrShuffleGrouping, which means that if the downstream bolt has a task on the same local worker, the output will only go to those tasks.
Options used by the flatMapping stage of a storm topology.
This value is mulitplied by the summer parallelism to set the true value used to hash and shard the key/value pairs.
SinkParallelism controls the number of executors storm allocates to the groupAndSum bolts.
This workaround is necessary because val parameters can't be call-by-name.
See FlatMapOptions.