* This I/O will form the basis of the new serialiser - it will simply
read to or write from one of these I/O streams. Then that stream can
come from a file, go to a memory buffer, or go through a compressor
or decompressor transparently.
* It also allows a unified way of writing over sockets instead of
needing special socket helper functions.
* With this commit, the code isn't used aside from in tests.