A native database backed by a single Mutex<SqliteConnection> instead of a
pool. Costs exactly one file descriptor. Chosen via the single_connection
builder flag — useful for services that run many clients in one process
(where a per-client pool would exhaust the OS file-descriptor limit) and do
serial work per client. There is no connection reentrancy in the codebase,
so a non-reentrant Mutex is safe (see the design spec).
An Unencrypted Connection
Creates a Sqlite3 Database/Connection in WAL mode.
_NOTE:_Unencrypted Connections are not validated and mostly meant for testing.
It is not recommended to use an unencrypted connection in production.