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/read_long.ts

@@ -0,0 +1,25 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
+import { type BufReader } from "./buf_reader.ts";
+import { readInt } from "./read_int.ts";
+
+const MAX_SAFE_INTEGER = BigInt(Number.MAX_SAFE_INTEGER);
+
+/**
+ * Read big endian 64bit long from BufReader
+ * @param buf
+ */
+export async function readLong(buf: BufReader): Promise<number | null> {
+  const high = await readInt(buf);
+  if (high === null) return null;
+  const low = await readInt(buf);
+  if (low === null) throw new Deno.errors.UnexpectedEof();
+  const big = (BigInt(high) << 32n) | BigInt(low);
+  // We probably should provide a similar API that returns BigInt values.
+  if (big > MAX_SAFE_INTEGER) {
+    throw new RangeError(
+      "Long value too big to be represented as a JavaScript number.",
+    );
+  }
+  return Number(big);
+}