method Buffer.swap64
Usage in Deno
```typescript import { type Buffer } from "node:node__buffer.d.ts"; ```
Buffer.swap64(): this
Interprets `buf` as an array of 64-bit numbers and swaps byte order _in-place_.
Throws `ERR_INVALID_BUFFER_SIZE` if `buf.length` is not a multiple of 8.
```js
import { Buffer } from 'node:buffer';
const buf1 = Buffer.from([0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8]);
console.log(buf1);
// Prints:
buf1.swap64();
console.log(buf1);
// Prints:
const buf2 = Buffer.from([0x1, 0x2, 0x3]);
buf2.swap64();
// Throws ERR_INVALID_BUFFER_SIZE.
```
this
A reference to `buf`.