Dapper cancelling only ExecuteReaderAsync not Reader.ReadAsync with MultiMap

Dapper will fail with such Test

        async Task<IEnumerable<Product>> Test()
        {
            CancellationTokenSource cancel = new CancellationTokenSource();
                try
                {
                    const string sql = @"select 1 as id, 'abc' as name, 2 as id, 'def' as name
union all select 1 as id, 'abc' as name, 2 as id, 'def' as name";
                    var productQuery = await connection.QueryAsync<Product, Category, Product>(new CommandDefinition(sql, cancellationToken: cancel.Token), (p, c) => {
                        p.Category = c;
                        //we cancel it in the middle of reading
                        cancel.Cancel();
                        return p;
                    }).ConfigureAwait(false);
                    return productQuery;
                }
                catch (Exception agg)
                {
                    //should be SqlException with message canceled
                }
            return null;
        }

        public async Task TestCancelInReaderReadAsync()
        {
            var res = await Test();
            res.IsEqualTo(null);
        }

solution:
replace all code like(in SQlMapper.Async.cs):

using (var cmd = (DbCommand)command.SetupCommand(cnn, info.ParamReader))
{
/*...*/
}

with

using (var cmd = (DbCommand)command.SetupCommand(cnn, info.ParamReader))
{
     using (var reg = command.CancellationToken.Register(() => cmd.Cancel()))
     {
/*...*/
     }
}

solution is simillar to this answer on SO but he is doing it at wrong place (and not dissposing the registration) ...

Start in SqlMapper.Async.cs, locating the asynchronous command and reader paths represented by the issue's using block. Reproduce the shown multi-map query with cancellation during mapping, then verify that cancellation reaches the reader and produces the expected cancelled-operation behavior without leaving registrations undisposed.