// The responses for fetching the object when If-Modified-Since
// and If-Unmodified-Since headers set are validated.
// If-Modified-Since - Return the object only if it has been modified since the specified time, else return a 304 (not modified).
// If-Unmodified-Since - Return the object only if it has not been modified since the specified time, else return a 412 (precondition failed).

      if (!status->status.ok()) {
        // Contract is we always delete input_values[i].
        return false;
      }
      // Note: session->session is not modified if Extend() fails, so
      // we only set last_num_graph_nodes if it succeeds.
      session->last_num_graph_nodes = num_nodes;
    } else {
      session->graph->mu.unlock();
    }
  }
  return true;
}

		copySourceHeader     string // data for "X-Amz-Copy-Source" header. Contains the object to be copied in the URL.
		copyModifiedHeader   string // data for "X-Amz-Copy-Source-If-Modified-Since" header
		copyUnmodifiedHeader string // data for "X-Amz-Copy-Source-If-Unmodified-Since" header
		copySourceSame       bool
		metadataGarbage      bool
		metadataReplace      bool
		metadataCopy         bool