Hide the key error tb on remote starting errors

tractor/_portal.py

@@ -428,12 +428,12 @@ class Portal:
             first = msg['started']
             ctx._started_called = True
 
-        except KeyError:
+        except KeyError as kerr:
             assert msg.get('cid'), ("Received internal error at context?")
 
             if msg.get('error'):
-                # raise the error message
-                raise unpack_error(msg, self.channel)
+                # raise kerr from unpack_error(msg, self.channel)
+                raise unpack_error(msg, self.channel) from None
             else:
                 raise
 

tractor/_streaming.py

@@ -425,7 +425,6 @@ class Context:
                 f'Remote context error for {self.chan.uid}:{self.cid}:\n'
                 f'{msg["error"]["tb_str"]}'
             )
-            # await ctx._maybe_error_from_remote_msg(msg)
             self._error = unpack_error(msg, self.chan)
 
             # TODO: tempted to **not** do this by-reraising in a