This is one way of partially addressing https://github.com/ziglang/zig/issues/24767

- These functions are unused
- These functions are untested
- These functions are broken
  + The same dangling pointer bug from 6219c015d8e8c958d96e5caa5ef0dbab9c414996 exists in `writePreserve`
  + The order of the bytes preserved in relation to the `bytes` being written can differ depending on unused buffer capacity at the time of the call and the drain implementation.

If there ends up being a need for these functions, they can be fixed and added back.