Chore: async write stream & mkdirp

Build/lib/async-write-to-stream.ts

@@ -0,0 +1,9 @@
+import type { Writable } from 'node:stream';
+import { once } from 'node:events';
+
+export const asyncWriteToStream = <T>(stream: Writable, chunk: T) => {
+  const res = stream.write(chunk);
+  if (!res) {
+    return once(stream, 'drain'); // returns a promise only if needed
+  }
+};