Parallel Work

Named durable branches replace graph split/join tokens.

final checks = await flow.parallel(
  id: 'checks',
  branches: {
    'risk': (branch) => branch.serviceTask(riskCheck, order, id: 'risk'),
    'credit': (branch) => branch.serviceTask(creditCheck, order, id: 'credit'),
  },
);

if (checks['risk']!.rejected || checks['credit']!.rejected) {
  return Result.rejected();
}

For "first success wins":

final quote = await flow.race(
  id: 'quotes',
  branches: {
    'internal': (branch) => branch.serviceTask(internalQuote, order, id: 'internal'),
    'external': (branch) => branch.call(vendorWorkflow, order, id: 'external'),
  },
);

Loser cancellation commits with the join. A late loser completion is rejected. Use onCancel when a started side effect needs cleanup.

See Also

• Structured Concurrency
• Control Flow