[codex] close iOS runner responses gracefully (#306)

* fix: close iOS runner responses gracefully

* fix: close runner connection after send

ios-runner/AgentDeviceRunner/AgentDeviceRunnerUITests/RunnerTests+Transport.swift

@@ -21,27 +21,39 @@ extension RunnerTests {
           status: 413,
           response: Response(ok: false, error: ErrorPayload(message: "request too large"))
         )
-        connection.send(content: response, completion: .contentProcessed { [weak self] _ in
-          connection.cancel()
+        self.sendResponse(response, over: connection) { [weak self] in
           self?.finish()
-        })
+        }
         return
       }
       let combined = buffer + data
       if let body = self.parseRequest(data: combined) {
         let result = self.handleRequestBody(body)
-        connection.send(content: result.data, completion: .contentProcessed { _ in
-          connection.cancel()
+        self.sendResponse(result.data, over: connection) { [weak self] in
           if result.shouldFinish {
-            self.finish()
+            self?.finish()
           }
-        })
+        }
       } else {
         self.receiveRequest(connection: connection, buffer: combined)
       }
     }
   }
 
+  private func sendResponse(
+    _ response: Data,
+    over connection: NWConnection,
+    afterSend: @escaping () -> Void = {}
+  ) {
+    connection.send(content: response, isComplete: true, completion: .contentProcessed { error in
+      if let error {
+        NSLog("AGENT_DEVICE_RUNNER_SEND_FAILED=%@", String(describing: error))
+      }
+      connection.cancel()
+      afterSend()
+    })
+  }
+
   private func parseRequest(data: Data) -> Data? {
     guard let headerEnd = data.range(of: Data("\r\n\r\n".utf8)) else {
       return nil