Vendor dependencies

Let's see how I like this workflow.

vendor/tokio/src/fs/symlink_dir.rs

@@ -0,0 +1,19 @@
+use crate::fs::asyncify;
+
+use std::io;
+use std::path::Path;
+
+/// Creates a new directory symlink on the filesystem.
+///
+/// The `dst` path will be a directory symbolic link pointing to the `src`
+/// path.
+///
+/// This is an async version of [`std::os::windows::fs::symlink_dir`][std]
+///
+/// [std]: std::os::windows::fs::symlink_dir
+pub async fn symlink_dir(src: impl AsRef<Path>, dst: impl AsRef<Path>) -> io::Result<()> {
+    let src = src.as_ref().to_owned();
+    let dst = dst.as_ref().to_owned();
+
+    asyncify(move || std::os::windows::fs::symlink_dir(src, dst)).await
+}