code: public java.lang.String getFilenameTensorName() {
      java.lang.Object ref = filenameTensorName_;
      if (ref instanceof java.lang.String) {
        return (java.lang.String) ref;
      } else {
        com.google.protobuf.ByteString bs = 
            (com.google.protobuf.ByteString) ref;
        java.lang.String s = bs.toStringUtf8();
        filenameTensorName_ = s;
        return s;
      }
    }
docs: <pre>
  The name of the tensor in which to specify the filename when saving or
  restoring a model checkpoint.
  </pre>
  
  <code>optional string filename_tensor_name = 1;</code>