Fixes:
Driver now closes connections on io errors, rather than relying on user. Issue when used in pools, when the client experienced a disconnect (resulting in an sqlexception). The pools often use a wrapper around the close, so a user attempting to close the connection could find the underlying bad connection would remain present (as the pool could attempt to keep it for future use when it wasnt yet marked as being closed via the 'isClosed' method). This could pollute the pool of connections.