private com.google.protobuf.SingleFieldBuilderV3<
            com.google.cloud.visionai.v1.Annotation,
            com.google.cloud.visionai.v1.Annotation.Builder,
            com.google.cloud.visionai.v1.AnnotationOrBuilder>
        getAnnotationFieldBuilder() {
      if (annotationBuilder_ == null) {
        annotationBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.cloud.visionai.v1.Annotation,
                com.google.cloud.visionai.v1.Annotation.Builder,
                com.google.cloud.visionai.v1.AnnotationOrBuilder>(
                getAnnotation(), getParentForChildren(), isClean());
        annotation_ = null;
      }
      return annotationBuilder_;
    }
<pre>
Required. The annotation to create.
</pre>

<code>
.google.cloud.visionai.v1.Annotation annotation = 2 [(.google.api.field_behavior) = REQUIRED];
</code>
java-visionai/proto-google-cloud-visionai-v1/src/main/java/com/google/cloud/visionai/v1/CreateAnnotationRequest.java