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

    size = 0;
    if (valueCase_ == 1) {
      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, value_);
    }
    if (valueCase_ == 2) {
      size +=
          com.google.protobuf.CodedOutputStream.computeInt64Size(
              2, (long) ((java.lang.Long) value_));
    }
    if (valueCase_ == 3) {
      size +=
          com.google.protobuf.CodedOutputStream.computeMessageSize(
              3, (com.google.type.DateTime) value_);
    }
    size += getUnknownFields().getSerializedSize();
    memoizedSize = size;
    return size;
  }
<pre>
Datetime type value.
</pre>

<code>.google.type.DateTime datetime_value = 3;</code>
java-visionai/proto-google-cloud-visionai-v1/src/main/java/com/google/cloud/visionai/v1/FacetValue.java