public Builder mergeBucketStart(com.google.cloud.visionai.v1.FacetValue value) {
        if (bucketStartBuilder_ == null) {
          if (((bitField0_ & 0x00000001) != 0)
              && bucketStart_ != null
              && bucketStart_ != com.google.cloud.visionai.v1.FacetValue.getDefaultInstance()) {
            getBucketStartBuilder().mergeFrom(value);
          } else {
            bucketStart_ = value;
          }
        } else {
          bucketStartBuilder_.mergeFrom(value);
        }
        if (bucketStart_ != null) {
          bitField0_ |= 0x00000001;
          onChanged();
        }
        return this;
      }
<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