Summary:
SetId and GetId are the experimental API that so far being used in WritePrepared and WriteUnPrepared transactions, where the id is assigned at the prepare time. The patch extends the API to WriteCommitted transactions, by setting the id at commit time.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4565

Differential Revision: D10557862

Pulled By: maysamyabandeh

fbshipit-source-id: 2b27a140682b6185a4988fa88f8152628e0d67af