method Deno.FsFile.prototype.sync
FsFile.prototype.sync(): Promise<void>
Flushes any pending data and metadata operations of the given file
stream to disk.
```ts
const file = await Deno.open(
"my_file.txt",
{ read: true, write: true, create: true },
);
await file.write(new TextEncoder().encode("Hello World"));
await file.truncate(1);
await file.sync();
console.log(await Deno.readTextFile("my_file.txt")); // H
```
Promise<void>