Microsoft Bot - MemoryStorage - Error - Etag conflict - botframework

Question

I am try to save data to the MemoryStorage in Microsoft Bot Frame Work (in .NET environment).
I am using this method for do it:
public static class StateManager
{
private static MemoryStorage _myStorage;
static StateManager()
{
_myStorage = new MemoryStorage();
}
public async static void Save(UserDetails userDetails)
{
var changes = new Dictionary<string, object>();
{
changes.Add("ud", userDetails);
}
await _myStorage.WriteAsync(changes, new CancellationToken());
}
}
until now it's always work fine. but suddenly i am getting this error:
System.Exception: Etag conflict. Original: 4 Current: 5
any idea how to solve this error? thanks!
edit - with solve
I got that the problem was that i push data to the memory twice in a row (without get the data between the tow pushes). it's mean that after i push data one time, i have to get the data from the storage before i push the data again.
My question now it's why? i cannot save data twice without get the data between the tow pushes?

Answer 1

Without more code, I wasn't able to replicate your issue. However, it sounds like you have a concurrency problem.
Your Save() method returns a void. You should instead use:
public async static Task Save(UserDetails userDetails)
Then, when saving, call with:
await StateManager.Save(userDetails).
However, you can save yourself the trouble of these kinds of things and use BotBuilder's built-in state storage. References:
Save User and Conversation Data
Core Bot Sample - This is an example of good user profile storage