The `Bytes` type represents binary data. It is used across the filesystem, HTTP, and crypto modules for binary I/O. The `bytes` module is not needed for basic usage - `Bytes` is a built-in type - but it provides encoding and decoding utilities.

```vary-snippet
import crypto
import fs

# Binary file I/O
let raw: Bytes = fs.read_bytes("image.png").unwrap()
fs.write_bytes("copy.png", raw).unwrap()

# Crypto operations accept and return Bytes
let hash = crypto.sha256(raw)
print(hash.hex())
```

## Encoding

| **Function** | **Returns** | **Description** |
|----------|-----------|-------------|
| `crypto.base64_encode(b)` | `Str` | Encode bytes as base64 string |
| `crypto.base64_decode(s)` | `Bytes` | Decode base64 string to bytes |
| `crypto.hex_encode(b)` | `Str` | Encode bytes as hex string |
| `crypto.hex_decode(s)` | `Bytes` | Decode hex string to bytes |

String convenience variants (`base64_encode_str`, `hex_encode_str`, etc.) accept and return `Str` for text-only workflows.

## Binary I/O

| **Module** | **Function** | **Description** |
|--------|----------|-------------|
| `fs` | `read_bytes(path)` | Read file as `Bytes` |
| `fs` | `write_bytes(path, data)` | Write `Bytes` to file |
| `http` | response `.body_bytes()` | HTTP response body as `Bytes` |
| `crypto` | `random_bytes(n)` | Generate n random bytes |