Add option returnBuffers=true to the various ScanIterators

[0xgeert]

As asked here

it seems the various ScanIterators don't support returnBuffers: true
This would be a useful feature

[jsommer1738]

I would like this to be added to the GET command as well. Why is the option to return buffers not globally available?

[leibale]

@0xgeert this feature is already implemented in v5, stay tuned.. ;)
(we moved type mapping to be on the client rather than per command invocation, see here. any suggestions/improvements are welcome..)

@jsommer1738 you can use "return buffers" with any command:

await client.get(
  commandOptions({ returnBuffers: true }),
  'key'
); // Buffer | null