public StreamSubscriptionMock(
     StreamRefMock <TItem> stream,
     Func <StreamMessage, Task> callback,
     SubscribeOptions subscribe = null,
     ResumeOptions resume       = null)
     : base(stream, null, Guid.NewGuid())
 {
     this.stream      = stream;
     Callback         = callback;
     SubscribeOptions = subscribe;
     ResumeOptions    = resume;
 }
        StreamRefMock GetOrCreateMock(StreamPath path)
        {
            if (streams.ContainsKey(path))
            {
                return(streams[path]);
            }

            var mock = new StreamRefMock(path, serialization);

            streams.Add(path, mock);

            return(mock);
        }