var sql = """
SELECT
    *
FROM
    Widgets
WHERE
    AccountId = @AccountId
ORDER BY
    SomeField
""";

using (var conn = new SqlConnection(config.GetConnectionString("MyConnectionString")))
{
    await foreach (var widget in conn.QueryUnbufferedAsync<WidgetModel>(query, new { accountId }))
    {
        // Do something with each record
    }
}