Response Variables property is not very convenient

[xlegalles]

The response Variablesproperty is a string and this is not very convenient: the proof is the addition of a getVariablesAsMap method in the java client.

The solution would be to add the same kind of facilities in the C# client: GetVariablesAsMapand GetVariablesAsType(names are the same as the java ones) that return respectively an IReadOnlyDictionary<string, object> and T.

Remaining questions are:

• the choice of a JSON serializer i.e. Newtonsoft Json.NET vs MS System.Text.Json as we would add a new dependency to the client. For testing you use the 1st one.
• and this dependency would be exposed because in the IReadOnlyDictionary<string, object>, the value could be a JObject.

I can make a PR if you agree.

Thank you

[Zelldon]

I will close this, since after discussion we also closed the related PR :) https://github.com/camunda-community-hub/zeebe-client-csharp/pull/220 feel free to reopen it if you disagree.