Reuse scoped content and progress operations

src/serviceFeatures/replication/ReplicateResultProcessor.counting.unit.spec.ts

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+import { reactiveSource } from "octagonal-wheels/dataobject/reactive";
+import { promiseWithResolvers } from "octagonal-wheels/promises";
+import { describe, expect, it } from "vitest";
+import { ReplicateResultProcessor } from "./ReplicateResultProcessor";
+
+describe("ReplicateResultProcessor.withCounting", () => {
+    it("counts overlapping callbacks until each settles and preserves results and errors", async () => {
+        const originalCount = 7;
+        const count = reactiveSource(originalCount);
+        const processor = new ReplicateResultProcessor({} as never);
+        const firstResult = { task: "first" };
+        const firstResultGate = promiseWithResolvers<typeof firstResult>();
+        const secondResultGate = promiseWithResolvers<string>();
+        const firstStarted = promiseWithResolvers<undefined>();
+        const secondStarted = promiseWithResolvers<undefined>();
+        const failure = new Error("second callback failed");
+        let firstCountAtStart = 0;
+        let secondCountAtStart = 0;
+
+        const first = processor.withCounting(async () => {
+            firstCountAtStart = count.value;
+            firstStarted.resolve(undefined);
+            return firstResultGate.promise;
+        }, count);
+        await firstStarted.promise;
+        expect(firstCountAtStart).toBe(originalCount + 1);
+        expect(count.value).toBe(originalCount + 1);
+
+        const second = processor.withCounting(async () => {
+            secondCountAtStart = count.value;
+            secondStarted.resolve(undefined);
+            return secondResultGate.promise;
+        }, count);
+        await secondStarted.promise;
+        expect(secondCountAtStart).toBe(originalCount + 2);
+        expect(count.value).toBe(originalCount + 2);
+
+        firstResultGate.resolve(firstResult);
+        await expect(first).resolves.toBe(firstResult);
+        expect(count.value).toBe(originalCount + 1);
+
+        secondResultGate.reject(failure);
+        await expect(second).rejects.toBe(failure);
+        expect(count.value).toBe(originalCount);
+    });
+});