Net::FTP connection status

How can I determine if a Net::FTP connection is still up?

We have an app that transfers anything from 1 to several hundred files
in a session. Occasionally the connection seems to drop (though
netstat on the server says its still up) I would like to be able to
query the status of the connection before each 'put'.
The only way we can see how is to do an 'ls' or 'pwd' and then check
$@ if they fail.

Any better way ?

Thanks

Steve