Container class that includes optional information about a parallelDo operation
applied to a PCollection. Primarily used within the Crunch framework
itself for certain types of advanced processing operations, such as in-memory joins
that require reading a file from the filesystem into a DoFn.
public void configure(org.apache.hadoop.conf.Configuration conf)
Applies the key-value pairs that were associated with this instance to the given Configuration
object. This is called just before the configure method on the DoFn corresponding to this
instance is called, so it is possible for the DoFn to see (and possibly override) these settings.