We need the transparent account privkey in order to be able to derive
the secret key for any leaf transparent address under the ZIP 316
diversified address tree.
UnifiedViewingKey had a bug that made it incompatible with ZIP 316.
For compatibility with the current `zcash/librustzcash` revision we use
a temporary fake UFVK encoding that stores sufficient information to use
the current APIs, and a superset of the actual ZIP 316 FVK information.
- Replace int with type safe BlockHeight(Long) object
- Fix down casting bug, as BlockHeight is uint32 but Java only supports int32 or int64
- Rename WalletBirthday to Checkpoint and hide from the public API
While there are a lot of changes, the most significant are:
- Update the main entrypoint of the SDK to use a suspending function and eliminate lazy initialization. This also resolves#310
- Changing Dao methods to `suspend`, allowing Room to implicitly manage the threading model under the hood
- Explicitly set the executor thread for the `CompactBlockDb` and `DerivedDataDb`, which is the same thread used when calling into the Rust native library. Room will then use this thread for `suspend` fun calls into it
- With the above set, remove unnecessary hops to Dispatchers.IO which is a thread pool
- Eliminate lazy initialization in `PagedTransactionRepository` to make it easier to reason about the threading model and resolve#355 where the database was being touched from the UI thread
Note that `PendingTransactionsDb` is not opted into this single-threaded approach, because that database is not shared with the Rust code
To quickly get this implemented, some calls in the demo-app have been wrapped in `runBlocking {}`. This is not ideal and will be addressed in followup issues.
Jack Grigg
Carter Jernigan