private com.google.protobuf.SingleFieldBuilderV3<
              com.google.cloud.visionai.v1.FacetValue,
              com.google.cloud.visionai.v1.FacetValue.Builder,
              com.google.cloud.visionai.v1.FacetValueOrBuilder>
          getBucketStartFieldBuilder() {
        if (bucketStartBuilder_ == null) {
          bucketStartBuilder_ =
              new com.google.protobuf.SingleFieldBuilderV3<
                  com.google.cloud.visionai.v1.FacetValue,
                  com.google.cloud.visionai.v1.FacetValue.Builder,
                  com.google.cloud.visionai.v1.FacetValueOrBuilder>(
                  getBucketStart(), getParentForChildren(), isClean());
          bucketStart_ = null;
        }
        return bucketStartBuilder_;
      }
<pre>
Lower bound of the bucket. NOTE: Only integer type is currently supported
for this field.
</pre>

<code>.google.cloud.visionai.v1.FacetValue bucket_start = 1;</code>
java-visionai/proto-google-cloud-visionai-v1/src/main/java/com/google/cloud/visionai/v1/FacetProperty.java