Replace RequestID with a tuple of TransactionID + RequestSeq

[dmitrii-ubskii]

Problem to Solve

UUIDv4 generation is quite costly, and generating a new one for each query in rapid succession (during e.g. data ingestion) can make it a bottleneck.

Proposed Solution

Generate UUID once for the transaction and append a sequence number for each request in a transaction, or move away from uuids altogether.

[alexjpwalker]

SequenceID makes sense. The current UUID implementation is a lazy, suboptimal way of generating unique IDs without needing to maintain additional client-side state.

TransactionID shouldn't be necessary as each bidirectional stream is scoped to a single Transaction.