refactor(server): simplify router middleware with next() (#21720)

packages/opencode/test/memory/abort-leak-webfetch.ts

@@ -0,0 +1,49 @@
+import { abortAfterAny } from "../../src/util/abort"
+
+const MB = 1024 * 1024
+const ITERATIONS = 50
+
+const heap = () => {
+  Bun.gc(true)
+  return process.memoryUsage().heapUsed / MB
+}
+
+const server = Bun.serve({
+  port: 0,
+  fetch() {
+    return new Response("hello from local", {
+      headers: {
+        "content-type": "text/plain",
+      },
+    })
+  },
+})
+
+const url = `http://127.0.0.1:${server.port}`
+
+async function run() {
+  const { signal, clearTimeout } = abortAfterAny(30000, new AbortController().signal)
+  try {
+    const response = await fetch(url, { signal })
+    await response.text()
+  } finally {
+    clearTimeout()
+  }
+}
+
+try {
+  await run()
+  Bun.sleepSync(100)
+  const baseline = heap()
+
+  for (let i = 0; i < ITERATIONS; i++) {
+    await run()
+  }
+
+  Bun.sleepSync(100)
+  const after = heap()
+  process.stdout.write(JSON.stringify({ baseline, after, growth: after - baseline }))
+} finally {
+  server.stop(true)
+  process.exit(0)
+}