This is the 2nd installment for the AccountsDb replication.
Summary of Changes
The basic google protocol buffer protocol for replicating updated slots and accounts. tonic/tokio is used for transporting the messages.
The basic framework of the client and server for replicating slots and accounts -- the persisting of accounts in the replica-side will be done at the next PR -- right now -- the accounts are streamed to the replica-node and dumped. Replication for information about Bank is also not done in this PR -- to be addressed in the next PR to limit the change size.
Functionality used by both the client and server side are encapsulated in the replica-lib crate.
There is no impact to the existing validator by default.
Tests:
Observe the confirmed slots replicated to the replica-node.
Observe the accounts for the confirmed slot are received at the replica-node side.