There's a been a todo for soo long for this XD
Since all `Actor`'s store a set of `._peers` we can try a lookup on that
table as a shortcut before pinging the registry Bo
Impl deats:
- add a new `._discovery.get_peer_by_name()` routine which attempts the
`._peers` lookup by combining a copy of that `dict` + an entry added
for `Actor._parent_chan` (since all subs have a parent and often the
desired contact is just that connection).
- change `.find_actor()` (for the `only_first == True` case),
`.query_actor()` and `.wait_for_actor()` to call the new helper and
deliver appropriate outputs if possible.
Other,
- deprecate `get_arbiter()` def and all usage in tests and examples.
- drop lingering use of `arbiter_sockaddr` arg to various routines.
- tweak the `Actor` doc str as well as some code fmting and a tweak to
the `._stream_handler()`'s initial `con_status: str` logging value
since the way it was could never be reached.. oh and `.warning()` on
any new connections which already have a `_pre_chan: Channel` entry in
`._peers` so we can start minimizing IPC duplications.
32f7742e53