PollingDuplexBindingElement for WCF duplex service in SL 2 Beta 2

Hello all,
While following through the document "How to: Create a Duplex Contract" at http://msdn.microsoft.com/en-us/library/ms731184.aspx, it states that
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"Note that the System.ServiceModel.PollingDuplex.dll is for evaluation
purposes only, and is not to be used in production environments."
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 What should be used for those of us that need polling duplex capabilities.  Do I need to write something myself?
 
Thanks,
James
 
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