Replace the sequential counting (which might be exhausted) by an address
of an object (in a box, so it doesn't change). This is also a unique, so
it is acceptable ID.
Add the driver task, connecting the signal handler wakeups to the
wakeups of of the streams.
It is a prototype-quality code, a lot of cleanups and similar is needed.
Which is just a wrapper around the futures::sync::mpsc. The sender is in
a global registry.
The part that connects the wakeups to the senders in the registry
doesn't yet exist.
Register the signal handler that wakes up someone through a self-pipe.
That someone doesn't yet exist, though.
Some dependencies (nix, lazy_static) added to speed up the prototyping
process. They are likely to be dropped in some future commits.
Some features (eg. preserving the previous signal handlers) are still
missing.
Alex Crichton