Why i'm getting this error:

You need to provide the sub process_bytes. Incoming bytes are fed to that sub. What you do in it is up to you.

And, how can I use IO::Socket::SSL ? There is only http example in manual.

Just like IO::Socket::INET. "This module is a true drop-in replacement for IO::Socket::INET that uses SSL to encrypt data before it is transferred to a remote server or client."