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_string_delim.ts

@@ -0,0 +1,37 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+// This module is browser compatible.
+
+import { type Reader } from "../types.d.ts";
+import { readDelim } from "./read_delim.ts";
+
+/**
+ * Read Reader chunk by chunk, splitting based on delimiter.
+ *
+ * @example
+ * ```ts
+ * import { readStringDelim } from "https://deno.land/std@$STD_VERSION/io/read_string_delim.ts";
+ * import * as path from "https://deno.land/std@$STD_VERSION/path/mod.ts";
+ *
+ * const filename = path.join(Deno.cwd(), "std/io/README.md");
+ * let fileReader = await Deno.open(filename);
+ *
+ * for await (let line of readStringDelim(fileReader, "\n")) {
+ *   console.log(line);
+ * }
+ * ```
+ */
+export async function* readStringDelim(
+  reader: Reader,
+  delim: string,
+  decoderOpts?: {
+    encoding?: string;
+    fatal?: boolean;
+    ignoreBOM?: boolean;
+  },
+): AsyncIterableIterator<string> {
+  const encoder = new TextEncoder();
+  const decoder = new TextDecoder(decoderOpts?.encoding, decoderOpts);
+  for await (const chunk of readDelim(reader, encoder.encode(delim))) {
+    yield decoder.decode(chunk);
+  }
+}