Clean up unused code and stale comment

Summary: See comments added in the diff for why removing them.

Differential Revision: D78295862

Author: pzhan9

hyperactor_mesh/src/actor_mesh.rs

@@ -82,7 +82,6 @@ where
         sender.clone(),
         actor_mesh_shape.clone(),
         message,
-        None, // TODO: reducer typehash
     )?;
 
     comm_actor_ref.send(

hyperactor_mesh/src/comm.rs

@@ -256,8 +256,6 @@ impl CommActor {
                 message.shape().clone(),
                 message.sender().clone(),
             );
-            // TODO(pzhang) split reply ports so children can reply to this comm
-            // actor instead of parent.
             cx.post(
                 cx.self_id()
                     .proc_id()

hyperactor_mesh/src/comm/multicast.rs

@@ -54,8 +54,6 @@ pub struct CastMessageEnvelope {
     dest_port: DestinationPort,
     /// The serialized message.
     data: ErasedUnbound,
-    /// typehash of the reducer used to accumulate the message in split ports.
-    pub reducer_typehash: Option<u64>,
     /// The shape of the cast.
     shape: Shape,
 }
@@ -67,7 +65,6 @@ impl CastMessageEnvelope {
         sender: ActorId,
         shape: Shape,
         message: M,
-        reducer_typehash: Option<u64>,
     ) -> Result<Self, anyhow::Error>
     where
         A: RemoteActor + RemoteHandles<IndexedErasedUnbound<M>>,
@@ -80,7 +77,6 @@ impl CastMessageEnvelope {
             sender,
             dest_port: DestinationPort::new::<A, M>(actor_name),
             data,
-            reducer_typehash,
             shape,
         })
     }
@@ -100,7 +96,6 @@ impl CastMessageEnvelope {
             sender,
             dest_port,
             data: ErasedUnbound::new(data),
-            reducer_typehash: None,
             shape,
         }
     }