@java.lang.Override
  public int getSerializedSize() {
    int size = memoizedSize;
    if (size != -1) return size;

    size = 0;
    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(categoryMask_)) {
      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, categoryMask_);
    }
    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(confidenceMask_)) {
      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(2, confidenceMask_);
    }
    size += getUnknownFields().getSerializedSize();
    memoizedSize = size;
    return size;
  }
<pre>
A one channel image which is encoded as an 8bit lossless PNG. The size of
the image will be the same as the original image. For a specific pixel,
darker color means less confidence in correctness of the cateogry in the
categoryMask for the corresponding pixel. Black means no confidence and
white means complete confidence.
</pre>

<code>string confidence_mask = 2;</code>

@return The bytes for confidenceMask.
java-visionai/proto-google-cloud-visionai-v1/src/main/java/com/google/cloud/visionai/v1/ImageSegmentationPredictionResult.java