[Task]: [RRIO] [Cache] Redis based DoFn supporting writes

[damondouglas]

What needs to happen?

The output of this task is a Redis based DoFn that supports cache writes. Implementation reuses the Call PTransform and therefore serves as a dependency.

Measures of Ready

• [Task]: [RRIO] [Call] PTransform executes user custom code without adaptive throttling #28711

Measures of Done

• class CacheWriteRedisFn<RequestT, ResponseT> extends DoFn<KV<RequestT, ResponseT>, KV<RequestT, ResponseT>>
• Tests validate that Redis cache contains encoded RequestT/ResponseT pairs
• Tests validate the encoded pairs are not corrupted

Issue Priority

Priority: 2 (default / most normal work should be filed as P2)