Await Unit Sequences

These diagrams show how the await unit model parks and resumes QUEUE_ASYNC executions.

Unary Await

Suspension is normal control flow. It should not be logged as a failed step or routed through recovery as an exception.

One-To-One Over Stream

ONE_TO_ONE over a Multi is a stream of unary awaits inside one owning unit. This is the model used by csv-payments: each PaymentRecord is one input unit and each provider completion is one output unit.

Completion may arrive out of order. Replay preserves input order by reading completed item interactions by itemIndex.

Aggregate Unit

ONE_TO_MANY, MANY_TO_ONE, and MANY_TO_MANY are aggregate interaction units. The runtime materializes the relevant side of the boundary so replay has one stable unit to restart.

This deliberately avoids partial-output checkpointing inside the interaction unit. TPF owns retry/replay of the unit as a whole.

Timeout And Resume

Completion admission follows the opposite path: complete the interaction, update the unit, and resume the execution only when the unit is complete.