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>
Required. The list of fields to update. Update mask supports a special
value `*` which fully replaces (equivalent to PUT) the resource provided.
</pre>

<code>.google.protobuf.FieldMask update_mask = 2 [(.google.api.field_behavior) = REQUIRED];
</code>
java-telcoautomation/proto-google-cloud-telcoautomation-v1alpha1/src/main/java/com/google/cloud/telcoautomation/v1alpha1/UpdateHydratedDeploymentRequest.java