private com.google.protobuf.SingleFieldBuilderV3<
            com.google.protobuf.FieldMask,
            com.google.protobuf.FieldMask.Builder,
            com.google.protobuf.FieldMaskOrBuilder>
        getUpdateMaskFieldBuilder() {
      if (updateMaskBuilder_ == null) {
        updateMaskBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.protobuf.FieldMask,
                com.google.protobuf.FieldMask.Builder,
                com.google.protobuf.FieldMaskOrBuilder>(
                getUpdateMask(), getParentForChildren(), isClean());
        updateMask_ = null;
      }
      return updateMaskBuilder_;
    }
<pre>
A mask used to specify which fields of the queue are being updated.

If empty, then all fields will be updated.
</pre>

<code>.google.protobuf.FieldMask update_mask = 2;</code>
java-tasks/proto-google-cloud-tasks-v2/src/main/java/com/google/cloud/tasks/v2/UpdateQueueRequest.java