Getting Consistent Views on Streaming Data?

Trialize is a tool that lets you test your queries for correctness and consistency. In the past, people have used hand written code to look over streaming data. What are the pitfalls in doing so? Do you have an example where you can say that certain things are never going to converge to an answer? I was particularly interested in something that i read on the web side, where you have consistent was the tone that was used when you try and solve it yourself.