Best way to represent a UUID in Avro?

Here's how I've been doing it:

{
    "name": "user_id",
    "type": "string",
    "logicalType": "UUID"
}

At the time of writing the logicalType for UUIDs is not documented but it is nonetheless supported, you can check the code here and verify so yourself: https://github.com/apache/avro/blob/branch-1.8/lang/java/avro/src/main/java/org/apache/avro/LogicalTypes.java#L71

And here the docs: https://avro.apache.org/docs/1.10.0/spec.html#UUID

So far, the only way I found is defining a custom UUID:

{
  "namespace" : "your.namespace",
  "type" : "fixed",
  "name" : "UUID",
  "size" : 16
}

I'm using Scala, so I also defined an implicit conversion between java.util.UUID and my custom UUID, so it's not that much of a hassle to use it.