Module timely::dataflow::operators::aggregation

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Aggregation operators of various flavors

Two traits, Aggregate and StateMachine, which support the accumulation of streamed information.

Aggregate accumulates records within times, and releases the accumulations once the time is complete.

StateMachine responds to a sequence of keyed events, maintaining and updating a state for each key. The user logic may produce output records for each transition, and optionally de-register the state to clean up when appropriate.

The two methods are often combined, using first Aggregate to reduce the volume of information, and then StateMachine to track an accumulation across timestamps.