When required, multiline responses are sent uninterrupted. Depending on the library/language you're using, you may be able to read from your buffer (client side) line-by-line. Just be careful that you handle the end of the stream gracefully if it's not properly terminated.
RFC 1939[
^]
You'll do well to open a telnet session and poke at the server to see what it does.
Cheers.