Add. `skt:on_close()` test
Add. `skt:on_close()` test

moteus/lzmq,zeromq/lzmq,LuaDist/lzmq-ffi,moteus/lzmq,bsn069/lzmq,LuaDist/lzmq-ffi,zeromq/lzmq,LuaDist/lzmq,LuaDist/lzmq,moteus/lzmq,zeromq/lzmq,bsn069/lzmq