MapSerializer fails to serialize custom Map implementation

[Maximilian Michels]

Hi folks,

After many year of Kryo 2.24.0, Apache Flink finally upgraded to Kryo 5.6.2 as part of the Flink 2.0.0 release. Unfortunately, we are seeing some issues downstream in the Apache Iceberg project with the MapSerializer.

I've created this ticket: https://github.com/EsotericSoftware/kryo/issues/1173. 

I thought I'd open a conversation here as well, in case any additional information is required. Thank you in advance for your time and effort!

Cheers,

Max