Packet::Connect.new(
 :client-identifier<mosquitto_sub_10888>,
 :will(Message.new(
	:topic<topic>,
	:payload(buf8.new('msg'.encode))
	:qos(At-least-once),
	:retain,
 )),
 :60keep-alive-interval,
)

10 2b 00 04  4d 51 54 54    04 2e  00 3c 00 13
6d 6f 73 71  75 69 74 74    6f 5f 73 75  62 5f 31 30
38 38 38 00  05 74 6f 70    69 63 00 03  6d 73 67
