When sending larger data chunks (100kb+) then the current rc1 dll has a build in delay - which grows rapidly and exponentially.
To be honest its a very dumb error too from a n00b textbook - I used a string += string instead of using a StringBuilder when building debug log info.
I had a case where I needed to send 2 mb xml to the server - and it took 4-5 minutes. Duh
So if you are sending larger chunks of data to the server and experience hangs - then poke me and I can build you a temporary dll that fixes this.
The bug is obviously now fixed and will be included in the next release.
/Thomas