Specifies if explicit or implicit SSL mode should be used
Use this property to specify if explicit or implicit SSL mode should be
used to establish secure connection to server. In explicit mode, the client
connects to the generic FTP port (21), and then sends AUTH command.
In implicit mode, the connection is performed to the dedicated port (usually 990),
and immediately starts SSL negotiation (without sending AUTH command).
Default value is 1 (explicit mode).