Improve performance numbers on diagram view

I think we should consider improving the performance number labels on the diagram view.

At first glance its not intuitive what the numbers represent.

I would expect the 1st number to be the number of messages. And the 2nd number the avg processing time.
But I suggest to make the 2nd number in a parenthesis.

3 (16 avg ms)

See screenshot.

Also remember to change the toop tip.