FlowProcess implementations provide a call-back interface into the current computing system. Each {@link cascading.operation.Operation} is given a reference to a particular implementation, allowing itto get configuration properties, send a "keep alive" ping, or to set a counter value.
Depending on the underlying system, FlowProcess instances are not continuous across all operations in a {@link Flow}. Thus, a call to {@link #increment(Enum,long)} may start incrementing from zero if the operation making the callbelongs to a subsequent 'job' or 'step' from any previous operations calling increment.
A FlowProcess is roughly a child of {@link FlowSession}. FlowSession is roughly one to one with a particular {@link Flow}. And every FlowSession will have one or more FlowProcesses.
@see FlowSession