How It Works: Error 18056 - The client was unable to reuse a session

This message has come across my desk a couple of times in the last week and when that happens I like to produce blog content.  The error is when you are trying to use a pooled connection and the reset of the connection state encounters an error.   Additional details are often logged in the SQL Server error log but the 'failure ID' is the key to understanding where to go next. Event ID: