public Builder setUpdateMask(com.google.protobuf.FieldMask.Builder builderForValue) {
      if (updateMaskBuilder_ == null) {
        updateMask_ = builderForValue.build();
      } else {
        updateMaskBuilder_.setMessage(builderForValue.build());
      }
      bitField0_ |= 0x00000002;
      onChanged();
      return this;
    }
<pre>
List of fields to be updated. If not present, the entire workflow
will be updated.
</pre>

<code>.google.protobuf.FieldMask update_mask = 2;</code>
java-workflows/proto-google-cloud-workflows-v1beta/src/main/java/com/google/cloud/workflows/v1beta/UpdateWorkflowRequest.java