Looking for a solid client side sockets library

Question

Nothing too fancy, but the following would be nice for .NET:

1. Be able to instantiate the object and hook up the MessageReceived and ConnectionChanged events (or ones with similar purposes).
2. Be able to send data (duh)
3. When data is received, it fires the MessageReceived event on the same thread that the object was created on (this would be nice, but not absolutely required).
4. Have a blocking and non-blocking options for connecting and possibly sending data.
5. Free and open source - nice to have.

Answer 1

What's wrong with System.Net.Socket?

Answer 2

On my travels for intro to sockets in .NET I came across:

An Introduction to Socket Programming in .NET using C# By .NETian

http://www.codeproject.com/KB/IP/socketsincsharp.aspx

I am a newbie on stackoverflow so can not add another hyper link. But also on the code project is a project that implements another layer on the .net clases:

An Asynchronous Socket Server and Client By Andre Azevedo