--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/third_party/libuv/src/win/async.c	Wed Jan 14 19:39:52 2026 -0800
@@ -0,0 +1,98 @@
+/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <assert.h>
+
+#include "uv.h"
+#include "internal.h"
+#include "atomicops-inl.h"
+#include "handle-inl.h"
+#include "req-inl.h"
+
+
+void uv__async_endgame(uv_loop_t* loop, uv_async_t* handle) {
+  if (handle->flags & UV_HANDLE_CLOSING &&
+      !handle->async_sent) {
+    assert(!(handle->flags & UV_HANDLE_CLOSED));
+    uv__handle_close(handle);
+  }
+}
+
+
+int uv_async_init(uv_loop_t* loop, uv_async_t* handle, uv_async_cb async_cb) {
+  uv_req_t* req;
+
+  uv__handle_init(loop, (uv_handle_t*) handle, UV_ASYNC);
+  handle->async_sent = 0;
+  handle->async_cb = async_cb;
+
+  req = &handle->async_req;
+  UV_REQ_INIT(req, UV_WAKEUP);
+  req->data = handle;
+
+  uv__handle_start(handle);
+
+  return 0;
+}
+
+
+void uv__async_close(uv_loop_t* loop, uv_async_t* handle) {
+  if (!((uv_async_t*)handle)->async_sent) {
+    uv__want_endgame(loop, (uv_handle_t*) handle);
+  }
+
+  uv__handle_closing(handle);
+}
+
+
+int uv_async_send(uv_async_t* handle) {
+  uv_loop_t* loop = handle->loop;
+
+  if (handle->type != UV_ASYNC) {
+    /* Can't set errno because that's not thread-safe. */
+    return -1;
+  }
+
+  /* The user should make sure never to call uv_async_send to a closing or
+   * closed handle. */
+  assert(!(handle->flags & UV_HANDLE_CLOSING));
+
+  if (!uv__atomic_exchange_set(&handle->async_sent)) {
+    POST_COMPLETION_FOR_REQ(loop, &handle->async_req);
+  }
+
+  return 0;
+}
+
+
+void uv__process_async_wakeup_req(uv_loop_t* loop, uv_async_t* handle,
+    uv_req_t* req) {
+  assert(handle->type == UV_ASYNC);
+  assert(req->type == UV_WAKEUP);
+
+  handle->async_sent = 0;
+
+  if (handle->flags & UV_HANDLE_CLOSING) {
+    uv__want_endgame(loop, (uv_handle_t*)handle);
+  } else if (handle->async_cb != NULL) {
+    handle->async_cb(handle);
+  }
+}