public com.google.protobuf.FieldMask getUpdateMask() {
      if (updateMaskBuilder_ == null) {
        return updateMask_ == null
            ? com.google.protobuf.FieldMask.getDefaultInstance()
            : updateMask_;
      } else {
        return updateMaskBuilder_.getMessage();
      }
    }
<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>

@return The updateMask.
java-workflows/proto-google-cloud-workflows-v1beta/src/main/java/com/google/cloud/workflows/v1beta/UpdateWorkflowRequest.java