Ok, I think I figure this out.

One wants to make a Socket and manually connect it asynchronously using
BeginConnect. A manual reset event can then time the attempt to connect,
and stall the caller until either the asynchronous connect activity
occurs, or else the timed manual reset event wait expires. Once a
manually connected socket has been made, the next issue is how to get
the TcpClient to use it. There is a Client property on TcpClient, but
one must derive a from TcpClient to use it.  I simply wrapped up all the
timeout enabled connect methods in this wrapper class. I provided
overlaods to the base class Connect routines which add a timeout
parameter. I chose to exclude the DNS work from the timeout.

- Lee