void dummy(ref int x) 
{
only here x is valid !, as soon as the program jumps back to where dummy was called 
from, x is invalid ! 

this works fine as long as we don't want to pass a permanent reference to a variable!
to make it permanent it would be necessary to stay as long in this scope, as we need the ref !
I tried that with Threads, but as mentioned - too much overhead and calling the function is 
at least as ugly as the lambda approach ...
}