Add an actor "state mutation" via messages example

examples/actors/mutate_remote_state.py

@@ -0,0 +1,51 @@
+from itertools import cycle
+from pprint import pformat
+
+import trio
+import tractor
+
+_snd_chan, _recv_chan = trio.open_memory_channel(100)
+_actor_state = {'some_state_stuff': None}
+
+
+async def update_local_state(msg: dict):
+
+    global _actor_state
+    actor = tractor.current_actor()
+
+    print(f'Yo we got a message {msg}')
+
+    # update the "actor state"
+    _actor_state.update(msg)
+
+    print(f'New local "state" for {actor.uid} is {pformat(_actor_state)}')
+
+    # we're done so exit this task running in the subactor
+
+
+async def main():
+    # Main process/thread that spawns one sub-actor and sends messages
+    # to it to update it's state.
+
+    actor_portals = []
+
+    # XXX: that subactor can **not** outlive it's parent, this is SC.
+    async with tractor.open_nursery() as tn:
+
+        portal = await tn.start_actor('even_boy', enable_modules=[__name__])
+        actor_portals.append(portal)
+
+        portal = await tn.start_actor('odd_boy', enable_modules=[__name__])
+        actor_portals.append(portal)
+
+        for i, (count, portal) in enumerate(
+            zip(range(100), cycle(actor_portals))
+        ):
+            await portal.run(update_local_state, msg={f'msg_{i}': count})
+
+    # blocks here indefinitely synce we spawned "daemon actors using
+    # .start_actor()`, you'll need to control-c to cancel.
+
+
+if __name__ == '__main__':
+    trio.run(main)