Add matrix room link

README.rst

@@ -47,11 +47,14 @@ No PyPi release yet!
 Feel like saying hi?
 --------------------
 This project is very much coupled to the ongoing development of
-``trio`` (i.e. ``tractor`` gets all its ideas from that brilliant
+``trio`` (i.e. ``tractor`` gets most of its ideas from that brilliant
 community). If you want to help, have suggestions or just want to
-say hi, please feel free to ping me on the `trio gitter channel`_!
+say hi, please feel free to reach us on in our `matrix channel`_.  If
+matrix seems too hip, we're also mostly all in the the `trio gitter
+channel`_!
 
 .. _trio gitter channel: https://gitter.im/python-trio/general
+.. _matrix channel: https://matrix.to/#/!tractor:matrix.org
 
 
 .. |travis| image:: https://img.shields.io/travis/goodboy/tractor/master.svg

tractor/msg.py

@@ -193,7 +193,7 @@ def pub(
             topics: Set[str],
             *args,
             # *,
-            task_name: str = None,
+            task_name: str = None,  # default: only one task allocated
             packetizer: Callable = None,
             **kwargs,
         ):
@@ -202,6 +202,7 @@ def pub(
                     f"{agen} must be called with a `task_name` named "
                     f"argument with a falue from {tasks}")
 
+            topics = set(topics)
             ss = current_actor().statespace
             lockmap = ss.setdefault('_pubtask2lock', task2lock)
             lock = lockmap[task_name]