Stream delay results as candidates complete

tests/test_proxy_monitor_tui.py

@@ -163,6 +163,37 @@ class ProxyMonitorTUITests(unittest.TestCase):
         )
         self.assertEqual(recommended, "fast")
 
+    def test_delay_results_are_yielded_before_slower_candidates_finish(self) -> None:
+        class ControlledClient:
+            def __init__(self) -> None:
+                self.slow_started = threading.Event()
+                self.release_slow = threading.Event()
+
+            def measure_delay(self, _target: str, candidate: str, **_kwargs: object) -> int:
+                if candidate == "slow":
+                    self.slow_started.set()
+                    self.release_slow.wait(timeout=2)
+                    return 300
+                self.slow_started.wait(timeout=2)
+                return 42
+
+        client = ControlledClient()
+        stream = self.mod.iter_measure_candidates(
+            client,
+            "pc",
+            ["slow", "fast"],
+            test_url="https://www.gstatic.com/generate_204",
+            timeout_ms=5000,
+            concurrency=2,
+        )
+        try:
+            candidate, result = next(stream)
+            self.assertEqual(candidate, "fast")
+            self.assertEqual(result, (42, "42 ms"))
+        finally:
+            client.release_slow.set()
+        self.assertEqual(list(stream), [("slow", (300, "300 ms"))])
+
     def test_machine_rows_preserve_monitor_order_and_status(self) -> None:
         rows = self.mod.normalize_machine_rows(
             {