Function awaitCompletionOrPause

packages/core/execution/src/engine.ts:517–528

(
    fiber: Fiber.Fiber<ExecuteResult, E>,
    pauseQueue: Queue.Queue<InternalPausedExecution<E>>,
  )

   * settles on whichever side completes first, success or failure.
   */
  const awaitCompletionOrPause = (
    fiber: Fiber.Fiber<ExecuteResult, E>,
    pauseQueue: Queue.Queue<InternalPausedExecution<E>>,
  ): Effect.Effect<ExecutionResult, E> =>
    Effect.raceFirst(
      Fiber.join(fiber).pipe(
        Effect.map((result): ExecutionResult => ({ status: "completed", result })),
      ),
      Queue.take(pauseQueue).pipe(
        Effect.map((paused): ExecutionResult => ({ status: "paused", execution: paused })),
      ),
    );

  /**
   * Start an execution in pause/resume mode.