Add files (#3826)

docs/guides/read-file/buffer.md

@@ -0,0 +1,19 @@
+---
+name: Read a file to a Buffer
+---
+
+The `Bun.file()` function accepts a path and returns a `BunFile` instance. The `BunFile` class extends `Blob` and allows you to lazily read the file in a variety of formats.
+
+To read the file into a `Buffer` instance, first use `.arrayBuffer()` to consume the file as an `ArrayBuffer`, then use `Buffer.from()` to create a `Buffer` from the `ArrayBuffer`.
+
+```ts
+const path = "/path/to/package.json";
+const file = Bun.file(path);
+
+const arrbuf = await file.arrayBuffer();
+const buffer = Buffer.from(arrbuf);
+```
+
+---
+
+Refer to [Binary data > Buffer](/docs/api/binary-data#buffer) for more information on working with `Buffer` and other binary data formats in Bun.