MultiMapAsync disposes reader in unbuffered query

[Qetu107oz]

1. Create unbuffered CommandDefinition with flags CommandFlags.None.
2. Call QueryAsync<TFirst, ..., TReturn>(command)

Dapper/Dapper/SqlMapper.Async.cs

Line 940 in 52160dc

using var reader = await ExecuteReaderWithFlagsFallbackAsync(cmd, wasClosed, CommandBehavior.SequentialAccess | CommandBehavior.SingleResult, command.CancellationToken).ConfigureAwait(false);