- A `HandleClass` class which supports common operations
- A `ReadHandle` class
  - Requires a `read` function to read a `Record` from the `Handle`.
  - A 'reader' function returning a `SourceT` of the `Record` of the
    underlying `HandleClass`.
- A `WriteHandle` class
  - Requires a `write` function that writes a `Record` to the `Handle`.
  - A `writer` function that produces a `ProcessT`:
    - Writes `Record`s to the underlying `Handle`
    - Passes `Record`s unchanged.

- A `ByteString` implementations for this
- Tests for the `ByteString` implementation