message: review updates:
  remove unused overload
diff: @@ -576,35 +576,12 @@ public:
  request i_send(std::shared_ptr<const Executor> exec,
  const SendType* send_buffer, const int send_count,
  const int destination_rank, const int send_tag) const
  - {
  - return i_send(std::move(exec), send_buffer, send_count,
  - type_impl<SendType>::get_type(), destination_rank,
  - send_tag);
  - }
  -
  - /**
  - * Send (Non-blocking, Immediate return) data from calling process to
  - * destination rank.
  - *
  - * @param exec The executor, on which the message buffer is located.
  - * @param send_buffer the buffer to send
  - * @param send_count the number of elements to send
  - * @param send_type the MPI_Datatype of the elements to send
  - * @param destination_rank the rank to send the data to
  - * @param send_tag the tag for the send call
  - *
  - * @return the request handle for the send call
  - */
  - request i_send(std::shared_ptr<const Executor> exec,
  - const void* send_buffer, const int send_count,
  - MPI_Datatype send_type, const int destination_rank,
  - const int send_tag) const
  {
  auto guard = exec->get_scoped_device_id();
  request req;
  - GKO_ASSERT_NO_MPI_ERRORS(MPI_Isend(send_buffer, send_count, send_type,
  - destination_rank, send_tag,
  - this->get(), req.get()));
  + GKO_ASSERT_NO_MPI_ERRORS(
  + MPI_Isend(send_buffer, send_count, type_impl<SendType>::get_type(),
  + destination_rank, send_tag, this->get(), req.get()));
  return req;
  }
  @@ -655,32 +632,12 @@ public:
  request i_recv(std::shared_ptr<const Executor> exec, RecvType* recv_buffer,
  const int recv_count, const int source_rank,
  const int recv_tag) const
  - {
  - return i_recv(std::move(exec), recv_buffer, recv_count,
  - type_impl<RecvType>::get_type(), source_rank, recv_tag);
  - }
  -
  - /**
  - * Receive (Non-blocking, Immediate return) data from source rank.
  - *
  - * @param exec The executor, on which the message buffer is located.
  - * @param recv_buffer the buffer to send
  - * @param recv_count the number of elements to receive
  - * @param recv_type the MPI_Datatype of the elements to receive
  - * @param source_rank the rank to receive the data from
  - * @param recv_tag the tag for the recv call
  - *
  - * @return the request handle for the recv call
  - */
  - request i_recv(std::shared_ptr<const Executor> exec, void* recv_buffer,
  - const int recv_count, MPI_Datatype recv_type,
  - const int source_rank, const int recv_tag) const
  {
  auto guard = exec->get_scoped_device_id();
  request req;
  - GKO_ASSERT_NO_MPI_ERRORS(MPI_Irecv(recv_buffer, recv_count, recv_type,
  - source_rank, recv_tag, this->get(),
  - req.get()));
  + GKO_ASSERT_NO_MPI_ERRORS(
  + MPI_Irecv(recv_buffer, recv_count, type_impl<RecvType>::get_type(),
  + source_rank, recv_tag, this->get(), req.get()));
  return req;
  }
  