find solution to the genericWriter + frankenObject problem

Nobody has claimed this yet.

if you create a genericRecord, populate some of its nested fields with specific objects (specifically you need an enum somewhere in the graph) when try and encode the object avro fails.
root cause is the specific enum instance will not be considered an enum by class GenericData.

this is very likely an avro bug, but this exists up to at least 1.10.1 and so a solution to existing avro is needed

Start by reproducing the failure with a genericRecord containing nested specific objects and an enum, then trace genericWriter through Avro's GenericData handling. Verify the solution against Avro versions through 1.10.1; done means the existing Avro setup can encode the populated record successfully.

Written by the indexing model from the issue text.