Avro output type for GCS sink doesn't use `schema.registry.url` to store schema

Hello,
I'm trying to use the GCS sink to output avro files. It works well but the schema is written in the file.
I haven't managed to make the connector write the schema in the schema registry provided in the `schema.registry.url` property.
I don't think `schema.registry.url` property is taken into account by the connector. I doesn't show up in the Kafka Connect logs, and has no effect.
Is it handled by the connector ? If so, can you provide an example ?
Thank you