com.twitter.summingbird.scalding
If this full stream for this batch is already materialized, return it
Instances may choose to write out materialized streams by implementing this.
Instances may choose to write out materialized streams by implementing this. This is what readStream returns.
in will completely cover these batches Return a new FlowToPipe with the write as a side effect
in will completely cover these batches Return a new FlowToPipe with the write as a side effect