Provide ShortByteString API

[hasufell]

ShortByteString now has the same API as ByteString. It has certain benefits and is used in the new OsPath type.

[hasufell]

I guess most of the optimization tricks rely on the fact that we can walk and shift around buffers in ByteString and Text without copying any data (which is not true for ShortByteString).

So a ShortByteString API would likely just do fromShort and toShort at the outer layers? I could attempt a full ShortByteString implementation, but my guess is that it would be magnitudes slower due to more copying.

[hasufell]

After writing my blog The ultimate guide to Haskell Strings I think the most sensible strategy is to:

• provide a Bytes API from the byteslice package
  • these can be pinned or unpinned
  • conversion from ShortByteString is O(1)
  • they can slice as efficiently as Text or ByteString
• then ShortByteString users can convert to Bytes and run the parser
• we also get ShortText support for free (conversion to Bytes is O(1) too)