Rename `PldRx.dec_msg()` -> `.decode_pld()`

Keep the old alias, but i think it's better form to use longer names for
internal public APIs and this name better reflects the functionality:
decoding and returning a `PayloadMsg.pld` field.

tractor/msg/_ops.py

@@ -167,7 +167,7 @@ class PldRx(Struct):
         ipc_msg: MsgType|None = None,
         expect_msg: Type[MsgType]|None = None,
         hide_tb: bool = False,
-        **dec_msg_kwargs,
+        **dec_pld_kwargs,
 
     ) -> Any|Raw:
         __tracebackhide__: bool = hide_tb
@@ -179,12 +179,12 @@ class PldRx(Struct):
             # sync-rx msg from underlying IPC feeder (mem-)chan
             ipc._rx_chan.receive_nowait()
         )
-        return self.dec_msg(
+        return self.decode_pld(
             msg,
             ipc=ipc,
             expect_msg=expect_msg,
             hide_tb=hide_tb,
-            **dec_msg_kwargs,
+            **dec_pld_kwargs,
         )
 
     async def recv_pld(
@@ -194,7 +194,7 @@ class PldRx(Struct):
         expect_msg: Type[MsgType]|None = None,
         hide_tb: bool = True,
 
-        **dec_msg_kwargs,
+        **dec_pld_kwargs,
 
     ) -> Any|Raw:
         '''
@@ -208,17 +208,14 @@ class PldRx(Struct):
             # async-rx msg from underlying IPC feeder (mem-)chan
             await ipc._rx_chan.receive()
         )
-        return self.dec_msg(
+        return self.decode_pld(
             msg=msg,
             ipc=ipc,
             expect_msg=expect_msg,
-            **dec_msg_kwargs,
+            **dec_pld_kwargs,
         )
 
-    # TODO: rename to,
+    def decode_pld(
-    # -[ ] `.decode_pld()`?
-    # -[ ] `.dec_pld()`?
-    def dec_msg(
         self,
         msg: MsgType,
         ipc: Context|MsgStream,
@@ -299,9 +296,6 @@ class PldRx(Struct):
                             if not is_started_send_side
                             else ipc._actor.uid
                         ),
-                        # tb=valerr.__traceback__,
-                        # tb_str=mte._message,
-                        # message=mte._message,
                     )
                     mte._ipc_msg = err_msg
 
@@ -317,29 +311,6 @@ class PldRx(Struct):
                     # validation error.
                     src_err = valerr
 
-                    # TODO: should we instead make this explicit and
-                    # use the above masked `is_started_send_decode`,
-                    # expecting the `Context.started()` caller to set
-                    # it? Rn this is kinda, howyousayyy, implicitly
-                    # edge-case-y..
-                    # TODO: remove this since it's been added to
-                    # `_raise_from_unexpected_msg()`..?
-                    # if (
-                    #     expect_msg is not Started
-                    #     and not is_started_send_side
-                    # ):
-                    #     # set emulated remote error more-or-less as the
-                    #     # runtime would
-                    #     ctx: Context = getattr(ipc, 'ctx', ipc)
-                    #     ctx._maybe_cancel_and_set_remote_error(mte)
-
-                # XXX some other decoder specific failure?
-                # except TypeError as src_error:
-                #     from .devx import mk_pdb
-                #     mk_pdb().set_trace()
-                #     raise src_error
-                # ^-TODO-^ can remove?
-
             # a runtime-internal RPC endpoint response.
             # always passthrough since (internal) runtime
             # responses are generally never exposed to consumer
@@ -435,6 +406,8 @@ class PldRx(Struct):
             __tracebackhide__: bool = False
             raise
 
+    dec_msg = decode_pld
+
     async def recv_msg_w_pld(
         self,
         ipc: Context|MsgStream,
@@ -463,7 +436,7 @@ class PldRx(Struct):
         # TODO: is there some way we can inject the decoded
         # payload into an existing output buffer for the original
         # msg instance?
-        pld: PayloadT = self.dec_msg(
+        pld: PayloadT = self.decode_pld(
             msg,
             ipc=ipc,
             expect_msg=expect_msg,
@@ -610,7 +583,10 @@ async def drain_to_final_msg(
             # only when we are sure the remote error is
             # the source cause of this local task's
             # cancellation.
-            ctx.maybe_raise()
+            ctx.maybe_raise(
+                # TODO: when use this/
+                # from_src_exc=taskc,
+            )
 
             # CASE 1: we DID request the cancel we simply
             # continue to bubble up as normal.
@@ -783,7 +759,7 @@ def validate_payload_msg(
     try:
         roundtripped: Started = codec.decode(msg_bytes)
         ctx: Context = getattr(ipc, 'ctx', ipc)
-        pld: PayloadT = ctx.pld_rx.dec_msg(
+        pld: PayloadT = ctx.pld_rx.decode_pld(
             msg=roundtripped,
             ipc=ipc,
             expect_msg=Started,