Drop the `Router.clients: set`, `.subscribers` is enough

piker/clearing/_ems.py

@@ -248,8 +248,6 @@ async def clear_dark_triggers(
 
                             await brokerd_orders_stream.send(brokerd_msg)
 
-                            # book._msgflows[oid].maps.insert(0, live_req)
-
                         case _:
                             raise ValueError(f'Invalid dark book entry: {cmd}')
 
@@ -333,9 +331,6 @@ class Router(Struct):
     # broker to book map
     books: dict[str, _DarkBook] = {}
 
-    # order id to client stream map
-    clients: set[tractor.MsgStream] = set()
-
     # sets of clients mapped from subscription keys
     subscribers: defaultdict[
         str,  # sub key, default fqsn
@@ -577,7 +572,6 @@ class Router(Struct):
                 trio.BrokenResourceError,
             ):
                 to_remove.add(client_stream)
-                self.clients.remove(client_stream)
                 log.warning(
                     f'client for {client_stream} was already closed?')
 
@@ -1324,8 +1318,6 @@ async def _emsd_main(
         # register the client side before starting the
         # brokerd-side relay task to ensure the client is
         # delivered all exisiting open orders on startup.
-        _router.clients.add(client_stream)
-
         # TODO: instead of by fqsn we need a subscription
         # system/schema here to limit what each new client is
         # allowed to see in terms of broadcasted order flow
@@ -1345,20 +1337,11 @@ async def _emsd_main(
             )
 
         finally:
-            # try to remove client from "registry"
-            try:
-                _router.clients.remove(client_stream)
-            except KeyError:
-                log.warning(
-                    f'Stream {client_stream._ctx.chan.uid}'
-                    ' was already dropped?'
-                )
-
+            # try to remove client from subscription registry
             _router.subscribers[fqsn].remove(client_stream)
-            dialogs = _router.dialogs
-            for oid, client_streams in dialogs.items():
-                if client_stream in client_streams:
-                    client_streams.remove(client_stream)
+
+            for oid, client_streams in _router.dialogs.items():
+                client_streams.discard(client_stream)
 
                 # TODO: for order dialogs left "alive" in
                 # the ems this is where we should allow some
@@ -1368,6 +1351,6 @@ async def _emsd_main(
                 # from client, run some algo, etc.)
                 if not client_streams:
                     log.warning(
-                            f'Order dialog is being unmonitored:\n'
+                        f'Order dialog is not being monitored:\n'
                         f'{oid} ->\n{client_stream._ctx.chan.uid}'
                     )