An implementation of MailboxProcessor using TPL Dataflow.

Have a look at the following posts for details:

[TDF Agents I] (http://7sharpnine.com/2012/01/22/2012-01-22-fsharp-dataflow-agents-i//)
[TDF Agents II] (http://7sharpnine.com/2012/01/30/2012-01-24-fsharp-dataflow-agents-ii/)
[TDF Agents III] (http://7sharpnine.com/2012/02/20/2012-02-19-fsharp-dataflow-agents-iii/)

TODO: Add XmlDoc comments for the member functions. Most of the functions are the equivelent of the MailboxProcessor's apart from Scan and TryScan