Replace old docs with new docs repo (#24201)

docs/guides/binary/buffer-to-arraybuffer.mdx

@@ -0,0 +1,16 @@
+---
+title: Convert a Buffer to an ArrayBuffer
+sidebarTitle: "Buffer to ArrayBuffer"
+mode: center
+---
+
+The Node.js [`Buffer`](https://nodejs.org/api/buffer.html) class provides a way to view and manipulate data in an underlying `ArrayBuffer`, which is available via the `buffer` property.
+
+```ts
+const nodeBuf = Buffer.alloc(64);
+const arrBuf = nodeBuf.buffer;
+```
+
+---
+
+See [Docs > API > Binary Data](https://bun.com/docs/api/binary-data#conversion) for complete documentation on manipulating binary data with Bun.