Decouple registery addresses from binding addresses

tractor/_root.py

@@ -70,6 +70,9 @@ async def open_root_actor(
     # defaults are above
     arbiter_addr: tuple[str, int]|None = None,
     
+    # binding addrs for the transport layer server
+    trans_bind_addrs: list[tuple[str, int]] = [(_default_host, _default_port)],
+    
     name: str|None = 'root',
 
     # either the `multiprocessing` start method:
@@ -184,6 +187,8 @@ async def open_root_actor(
     )
     assert registry_addrs
     
+    assert trans_bind_addrs
+
     loglevel = (
         loglevel
         or log._default_loglevel
@@ -273,8 +278,6 @@ async def open_root_actor(
                 tuple(addr),  # TODO: just drop this requirement?
             )
 
-    trans_bind_addrs: list[tuple[str, int]] = []
-
     # Create a new local root-actor instance which IS NOT THE
     # REGISTRAR
     if ponged_addrs:
@@ -296,11 +299,6 @@ async def open_root_actor(
             loglevel=loglevel,
             enable_modules=enable_modules,
         )
-        # DO NOT use the registry_addrs as the transport server
-        # addrs for this new non-registar, root-actor.
-        for host, port in ponged_addrs:
-            # NOTE: zero triggers dynamic OS port allocation
-            trans_bind_addrs.append((host, 0))
 
     # Start this local actor as the "registrar", aka a regular
     # actor who manages the local registry of "mailboxes" of