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/io/slice_long_to_bytes.ts

@@ -0,0 +1,19 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+// This module is browser compatible.
+
+/**
+ * Slice number into 64bit big endian byte array
+ * @param d The number to be sliced
+ * @param dest The sliced array
+ */
+export function sliceLongToBytes(
+  d: number,
+  dest = Array.from<number>({ length: 8 }),
+): number[] {
+  let big = BigInt(d);
+  for (let i = 0; i < 8; i++) {
+    dest[7 - i] = Number(big & 0xffn);
+    big >>= 8n;
+  }
+  return dest;
+}