Evict UDTs from UserType cache on change
UDT classes are generated dynamically while receiving, and cached.
Need to introduce a mechanism to evict these when type change events are received.
present symptom: fields ALTER/ADDed to a type are not decoded until a session is restarted
easily reproduced in cqlsh
I believe this is addressed in the change set for PYTHON-413. Specifically, this commit makes the caching logic consider field names and types when deciding whether to build a new type.
Moving along for review with PYTHON-413.