message: Be a little more explicit in the event trace
diff: @@ -467,12 +467,13 @@ PoplarExecutor::MoveDeviceToHost(TensorControl* tc) {
  } else {
  current_engine_->readTensor(tc->output_handle, buf);
  }
  + if (profile_io_) {
  + AddEventRecord(tensorflow::IpuTraceEvent::DEVICE_TO_HOST_TRANSFER,
  + tc->output_handle, 0);
  + }
  tc->on_device = false;
  tc->output_handle.clear();
  tc->input_handle.clear();
  - if (profile_io_) {
  - AddEventRecord(tensorflow::IpuTraceEvent::DEVICE_TO_HOST_TRANSFER, "", 0);
  - }
  return port::Status::OK();
  }
  @@ -570,7 +571,7 @@ PoplarExecutor::ExecuteEngine(perftools::gputools::StreamExecutor* executor,
  tc->input_handle = mem.first;
  if (profile_io_) {
  AddEventRecord(tensorflow::IpuTraceEvent::HOST_TO_DEVICE_TRANSFER,
  - "", 0);
  + mem.first, 0);
  }
  }
  }
  