3 - Writing beyond the end of a mapped-simple-stream is funky; arguably,
4 it should signal an error.
6 - write-octets / read-octets handling of encapsulated streams is
9 - Implement socket-base-simple-stream and chunked transfer encoding.
11 - Implement string streams.
13 - Make sure the code examples for stream encapsulation from Franz work
15 - Test every single output function