OK to do heavy processing in async callbacks?

Yes, this is how asynchronous Sockets (Tcp client, listeners, etc.) are designed for use. You should always ensure that you invoke the end aysnc method and then do whatever processing you desire. Not invoking the EndAccept(), EndSEnd(), EndReceive(), etc., etc. methods leaves you potentially open to a memory leak, so it's always a good practice to follow.

I repeated the experiments of a CodeProject article on this topic and found the results for . NET 4 to be similar to what were described in 2003. Note that the article did not actually list the results for the problematic section but as I understand it the main issue still exists.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.