Room 2.8.4

Added a prepared statement cache to Room's connection pool when using a SQLiteDriver that does not internally have a pool, such as the BundledSQLiteDriver. This improves performance on repeated execution of the same SQL statement. Fix an issue where the actual / expected error message on schema validation was missing information. Fix an issue with Room's Kotlin code generation missing @Transaction DAO functions with type variables. Improve Room's SupportSQLite Wrapper performance by avoiding thread hops maintaining the same blocking behaviour as the SupportSQLiteDatabase APIs.