Use scoped access to the agent connection to ensure the vsock fds are
close(2)'d.
### Note
In a follow up I'd like to change `LinuxProcess` to dialing the agent
connection inside of `.start()`. I don't like needing to pass it an
agent connection. It has a reference to a vm so it can easily dial
inside itself if it needs to.
- The kqueue handlers for stdio didn't have logic to exit on zero byte
reads.
- The agent wasn't getting closed explicitly in .delete()
- In LinuxContainer we should call delete just for sanity, if for
nothing more than ensuring the agent vsock fd is closed.
Signed-off-by: Danny Canter <danny_canter@apple.com>
This is something I forgot to update ages ago. The field names, while
they do make sense, were different than the constructor names that
eventually set the fields themselves. This is kind of awkward, and I'd
much rather fix this now while it's much easier.
We'll need to update `container` after this
Signed-off-by: Danny Canter <danny_canter@apple.com>