worldwide, non-exclusive, no-charge, royalty-free, irrevocable
      (except as stated in this section) patent license to make, have made,
      use, offer to sell, sell, import, and otherwise transfer the Work,
      where such license applies only to those patent claims licensable
      by such Contributor that are necessarily infringed by their
      Contribution(s) alone or by combination of their Contribution(s)

      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
      (except as stated in this section) patent license to make, have made,
      use, offer to sell, sell, import, and otherwise transfer the Work,
      where such license applies only to those patent claims licensable
      by such Contributor that are necessarily infringed by their
      Contribution(s) alone or by combination of their Contribution(s)

	if err != nil {
		return nil, err
	}

	_, err = obj.Stat()
	if err != nil {
		return nil, err
	}

	return obj, nil
}

// TransferError will catch network errors during transfer.
// When TransferError() is called Close() will also
// be called, so we do not need to Wait() here.
func (w *writerAt) TransferError(err error) {
	_ = w.w.CloseWithError(err)
	_ = w.r.CloseWithError(err)

    
![Estimate costs](g3doc/images/compute_cost.png)

4 Pick the proper subgraphs from the alternative views for execution based on
costs(computation costs, transfer costs, quant/dequant costs). As shown in the
diagram below, since cross-device data transferring cost is high, even "G" + "H"
running on GPU maybe less efficient than "C" running on "CPU", we will still
pick "G" + "H" subgraph.

  // Configure graph collection in RunMetadata.
  virtual void SetShouldStoreGraphs(bool value) = 0;

  // Return the collected RunMetadata. This method will transfer the ownership
  // to the caller.
  virtual std::unique_ptr<RunMetadata> ExportRunMetadata() = 0;

  // For LLVM style RTTI.
  static bool classof(const AbstractContext* ptr) {

      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
      (except as stated in this section) patent license to make, have made,
      use, offer to sell, sell, import, and otherwise transfer the Work,
      where such license applies only to those patent claims licensable
      by such Contributor that are necessarily infringed by their
      Contribution(s) alone or by combination of their Contribution(s)

        if (!device) {
          LLVM_DEBUG(llvm::dbgs()
                     << "  No device for output #" << output_index << "\n");
          continue;
        }
        // Transfer the annotation to both region arguments
        for (Region* region : while_region.getRegions()) {
          BlockArgument arg = region->getArgument(output_index);
          LLVM_DEBUG(llvm::dbgs()

        if (contentLength == -1L && lowercaseHeader.startsWith("content-length:")) {
          contentLength = header.substring(15).trim().toLong()
        }
        if (lowercaseHeader.startsWith("transfer-encoding:") &&
          lowercaseHeader.substring(18).trim() == "chunked"
        ) {
          chunked = true
        }
      }

      val peek = dispatcher.peek()

      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
      (except as stated in this section) patent license to make, have made,
      use, offer to sell, sell, import, and otherwise transfer the Work,
      where such license applies only to those patent claims licensable
      by such Contributor that are necessarily infringed by their
      Contribution(s) alone or by combination of their Contribution(s)

      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
      (except as stated in this section) patent license to make, have made,
      use, offer to sell, sell, import, and otherwise transfer the Work,
      where such license applies only to those patent claims licensable
      by such Contributor that are necessarily infringed by their
      Contribution(s) alone or by combination of their Contribution(s)