ICMPv4.Packetand 'a kind = | Echo_reply : id_and_seq kind| Destination_unreachable : next_hop_mtu kind| Source_quench : unused kind| Redirect : Ipaddr.V4.t kind| Echo_request : id_and_seq kind| Time_exceeded : unused kind| Parameter_problem : pointer kind| Timestamp_request : id_and_seq kind| Timestamp_reply : id_and_seq kind| Information_request : id_and_seq kind| Information_reply : id_and_seq kindval ipaddr : Ipaddr.V4.t Bin.tval id_and_seq : (int * int) Bin.tval next_hop_mtu : next_hop_mtu Bin.tval to_bytes : 'a t -> bytes