Added a very complicated AsyncIterableReader class.

The class was already implemented in
"https://deno.land/std@0.144.0/streams/conversion.ts".  So, I litterally
lost 1 day of work!  I hate myself.

vendor/deno.land/std@0.188.0/path/separator.ts

@@ -0,0 +1,7 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+// This module is browser compatible.
+
+import { isWindows } from "../_util/os.ts";
+
+export const SEP = isWindows ? "\\" : "/";
+export const SEP_PATTERN = isWindows ? /[\\/]+/ : /\/+/;