Merge pull request #20 from repr-man/main

Remove parens that stop compiler spec from passing

Merge pull request #19 from savi-lang/update/latest-io

Update for latest `IO` library changes.

Merge pull request #18 from savi-lang/update/latest-io

Remove deprecated usage of `IO.Engine.new_tcp_connect!`.

Merge pull request #17 from savi-lang/deprecate/pending-reads

Deprecate the `TCP.Engine.pending_reads` method.

Merge pull request #12 from savi-lang/add/address-getters

Add getter methods for remote and local IP addresses and ports.

Merge pull request #7 from savi-lang/update/latest-savi

Update for breaking `AsioEvent` changes in latest Savi version.

Merge pull request #5 from savi-lang/update/savi-deprecations

Update away from deprecated names in latest Savi version.

Add capability-based security to protect all `TCP` actions.

Now we have the following hierarchy:

- `Env.Root`
  - `TCP.Connect.Auth`
    - `TCP.Connect.Ticket`
  - `TCP.Listen.Auth`
    - `TCP.Listen.Ticket`

Additionally we have `TCP.Accept.Ticket` which can only come from
an actual pending connection trying to connect to a TCP listener.

Attenuating through the hierarchy to create a connect ticket looks like this:
```savi
TCP.auth(env.root).connect.to(host, port)
```

Attentuating through the hierarchy to create a listen ticket looks like this:
```savi
TCP.auth(env.root).listen.on(host, port)
```

Add missing `:from` declaration for `OSError` dependency.

Add `TCP` library code.