Provides adaptors for explicitly specifying how strings should be handled with being serialised and deserialised. These adaptors are:
`raw()` - write the data exactly as in
`null_terminated` - ensure the string is written with a null terminator - strings with embedded null bytes are *not* allowed (but is only enforced in debug) as retrieving such a string would stop at the first embedded null. This is user error is mostly semantics.
`prefixed` - prefixes the length before the string, no terminator is written.
`prefixed_varint` - prefixes the length, encoded as a varint, no terminator is written. This is more compact but slower than `prefixed`
All adaptors can be used both as input and output, with the exception of `raw()`. Retrieving strings written using `raw` requires the user to know specifics about the string content (i.e. whether it has embedded nulls or its length), so `.get()` should be used.
