Add new ip_prefix functionality and example

Author: biaks

examples/CMakeLists.txt

@@ -14,6 +14,7 @@ function(add_example NAME_EXAMPLE REQUIRED_TARGETS)
 endfunction()
 
 add_example(ip_address    ip-sockets-cpp-lite)
+add_example(ip_prefix     ip-sockets-cpp-lite)
 add_example(udp_socket    ip-sockets-cpp-lite)
 add_example(tcp_socket    ip-sockets-cpp-lite)
 add_example(resolve_host  ip-sockets-cpp-lite)