Spark structured streaming schema evolution

Hi @kevinwallimann
First I'm aware of the [issue](https://github.com/AbsaOSS/ABRiS/issues/176)

I used abris to stream avro to delta table. As mentioned in the issue the schema evolution is not working neither using streaming or foreachbatch.

However using this [code](https://github.com/Orpheuz/SparkAvroSchemaEvolution) I'm able to update the schema for each message at least in the source the problem is that is never reflected on the sink (can be easily adapted to use abris by the way)

You said spark can't handle this out of the box I confirm but **do you've any idea how to implement it ?**
Thanks