diff --git a/tractor/msg.py b/tractor/msg.py
index 560e644..28e3405 100644
--- a/tractor/msg.py
+++ b/tractor/msg.py
@@ -1,9 +1,13 @@
 """
 Messaging pattern APIs and helpers.
+
+NOTE: this module is likely deprecated by the new bi-directional streaming
+support provided by ``tractor.Context.open_stream()`` and friends.
+
 """
 import inspect
 import typing
-from typing import Dict, Any, Set, Callable
+from typing import Dict, Any, Set, Callable, List, Tuple
 from functools import partial
 from async_generator import aclosing
 
@@ -20,7 +24,7 @@ log = get_logger('messaging')
 
 async def fan_out_to_ctxs(
     pub_async_gen_func: typing.Callable,  # it's an async gen ... gd mypy
-    topics2ctxs: Dict[str, set],
+    topics2ctxs: Dict[str, list],
     packetizer: typing.Callable = None,
 ) -> None:
     """Request and fan out quotes to each subscribed actor channel.
@@ -34,24 +38,27 @@ async def fan_out_to_ctxs(
 
         async for published in pub_gen:
 
-            ctx_payloads: Dict[str, Any] = {}
+            ctx_payloads: List[Tuple[Context, Any]] = []
 
             for topic, data in published.items():
                 log.debug(f"publishing {topic, data}")
+
                 # build a new dict packet or invoke provided packetizer
                 if packetizer is None:
                     packet = {topic: data}
+
                 else:
                     packet = packetizer(topic, data)
-                for ctx in topics2ctxs.get(topic, set()):
-                    ctx_payloads.setdefault(ctx, {}).update(packet),
+
+                for ctx in topics2ctxs.get(topic, list()):
+                    ctx_payloads.append((ctx, packet))
 
             if not ctx_payloads:
                 log.debug(f"Unconsumed values:\n{published}")
 
             # deliver to each subscriber (fan out)
             if ctx_payloads:
-                for ctx, payload in ctx_payloads.items():
+                for ctx, payload in ctx_payloads:
                     try:
                         await ctx.send_yield(payload)
                     except (
@@ -60,15 +67,24 @@ async def fan_out_to_ctxs(
                         ConnectionRefusedError,
                     ):
                         log.warning(f"{ctx.chan} went down?")
-                        for ctx_set in topics2ctxs.values():
-                            ctx_set.discard(ctx)
+                        for ctx_list in topics2ctxs.values():
+                            try:
+                                ctx_list.remove(ctx)
+                            except ValueError:
+                                continue
 
             if not get_topics():
                 log.warning(f"No subscribers left for {pub_gen}")
                 break
 
 
-def modify_subs(topics2ctxs, topics, ctx):
+def modify_subs(
+
+    topics2ctxs: Dict[str, List[Context]],
+    topics: Set[str],
+    ctx: Context,
+
+) -> None:
     """Absolute symbol subscription list for each quote stream.
 
     Effectively a symbol subscription api.
@@ -77,7 +93,7 @@ def modify_subs(topics2ctxs, topics, ctx):
 
     # update map from each symbol to requesting client's chan
     for topic in topics:
-        topics2ctxs.setdefault(topic, set()).add(ctx)
+        topics2ctxs.setdefault(topic, list()).append(ctx)
 
     # remove any existing symbol subscriptions if symbol is not
     # found in ``symbols``
@@ -85,10 +101,14 @@ def modify_subs(topics2ctxs, topics, ctx):
     for topic in filter(
         lambda topic: topic not in topics, topics2ctxs.copy()
     ):
-        ctx_set = topics2ctxs.get(topic)
-        ctx_set.discard(ctx)
+        ctx_list = topics2ctxs.get(topic)
+        if ctx_list:
+            try:
+                ctx_list.remove(ctx)
+            except ValueError:
+                pass
 
-        if not ctx_set:
+        if not ctx_list:
             # pop empty sets which will trigger bg quoter task termination
             topics2ctxs.pop(topic)
 
@@ -256,7 +276,7 @@ def pub(
                             respawn = True
             finally:
                 # remove all subs for this context
-                modify_subs(topics2ctxs, (), ctx)
+                modify_subs(topics2ctxs, set(), ctx)
 
                 # if there are truly no more subscriptions with this broker
                 # drop from broker subs dict