message: code clean data_collector
diff: @@ -176,9 +176,6 @@ DataCollector<TypeKey>::DataCollector(const Tensors<float>& label_tensors,
  ************************************/
  template <typename TypeKey>
  void DataCollector<TypeKey>::collect() {
  - const int LABEL_TAG_OFFSET = 100;
  -
  - {
  std::unique_lock<std::mutex> lock(stat_mtx_);
  while (stat_ != READY_TO_WRITE && stat_ != STOP) {
  stat_cv_.wait(lock);
  @@ -187,7 +184,6 @@ void DataCollector<TypeKey>::collect() {
  return;
  }
  - if (1) {
  // my turn
  CSRChunk<TypeKey>* chunk_tmp = nullptr;
  @@ -235,10 +231,8 @@ void DataCollector<TypeKey>::collect() {
  }
  csr_heap_->chunk_free_and_checkin();
  - }
  counter_++;
  stat_ = READY_TO_READ;
  - }
  stat_cv_.notify_all();
  }
  @@ -271,8 +265,6 @@ void DataCollector<TypeKey>::read_a_batch_to_device() {
  CudaDeviceContext context((*device_resources_)[i]->get_device_id());
  CK_CUDA_THROW_(cudaStreamSynchronize((*device_resources_)[i]->get_stream()));
  }
  - // stat_ = READY_TO_WRITE;
  - // stat_cv_.notify_all();
  }
  template <typename TypeKey>
  