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/bytes/starts_with.ts

@@ -0,0 +1,21 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+// This module is browser compatible.
+
+/** Returns true if the prefix array appears at the start of the source array,
+ * false otherwise.
+ *
+ * The complexity of this function is O(prefix.length).
+ *
+ * ```ts
+ * import { startsWith } from "https://deno.land/std@$STD_VERSION/bytes/starts_with.ts";
+ * const source = new Uint8Array([0, 1, 2, 1, 2, 1, 2, 3]);
+ * const prefix = new Uint8Array([0, 1, 2]);
+ * console.log(startsWith(source, prefix)); // true
+ * ```
+ */
+export function startsWith(source: Uint8Array, prefix: Uint8Array): boolean {
+  for (let i = 0, max = prefix.length; i < max; i++) {
+    if (source[i] !== prefix[i]) return false;
+  }
+  return true;
+}