$maxCount

Creating the stream.cs

EventStoreConnection connection = get your connection;
string streamName = GetStreamName(aggregate);

//try to read the slice
var slice = connection.ReadStreamEventsForward(streamName, 0, int.MaxValue, false);

if (slice.Status == SliceReadStatus.StreamNotFound)
{
  //create the stream if doesn't exist.
  //NOTE: isJson MUST be true for this to work.
    connection.CreateStream(streamName, Guid.NewGuid(), isJson: true, metadata: SnapshotMetadata.Bytes);
}

var events = slice.Events;
var @event = events.FirstOrDefault();

SnapshotMetadata.cs

    [DataContract]
    public class SnapshotMetadata
    {
        [DataMember(Name = "$maxCount")] public int MaxCount = 1;

        private SnapshotMetadata()
        {
        }

        private static readonly SnapshotMetadata Instance = new SnapshotMetadata();

        public static byte[] Bytes
        {
            get
            {
                return Encoding.UTF8.GetBytes(JsonConvert.SerializeObject(Instance));
            }
        }
    }