Since a bug in the new `MsgStream.aclose()` impl's drain block logic was
triggering an actual inf loop (by not ever canceller the streamer child
actor), make sure we put a loop limit on the `inf_streamer`()` XD
Also add a bit more deats to the test `print()`s in each actor and toss
in `debug_mode` fixture support.
This actually catches a lot of bugs to do with stream termination and
``MsgStream.subscribe()`` usage where the underlying stream closes from
the producer side. When this passes the broadcaster logic will have to
ensure non-lossy fan out semantics and closure tracking.
Not sure we even have a test for this yet. The main issue discovered by
a user project (https://github.com/adder46/wrath) was that a kbi raised
inside a block like this (with both recv-only and send-recv streams)
would not cancel on the first ctrl-c sent from console and instead
SIGiNT had to be repeatedly sent as many times as there are subactors in
the first level tree. This test catches that as well as just verifies
the basic side-by-side functionality.
Tyler Goodlet