Expose a prepare method

[algorithmiker]

First of all, thanks for the excellent package!
I finally don't have to start every project by db.execute("PRAGMA journal_mode=WAL;").

Anyways, I very often seem to use the following pattern with sqlite3:

class SomeService {
  PreparedStatement? _prepared;
  SomeData run(Database db) {
    prepared ??= db.prepare("select * from sqlite_master", persistent: true);
    return db.select(prepared);
  }
}

I wonder if this could be done via sqlite_async