Get the internal handle from the given regional handle.
Warning: This function should not be exported to or used by end-users
because it allows them to close the handle manually, which will defeat the
safety-guarantees that this package provides!
Tip: If you enable the ViewPatterns language extension you can use
internalHandle as a view-pattern as in the following example from the
resetDevice :: (pr `ParentOf` cr, MonadIO cr)
-> RegionalHandle USB.Device pr -> cr ()
resetDevice (internalHandle -> (DeviceHandle ...)) = ...