成员的完整列表，这些成员属于 neforce::dns_soa_record,包括所有继承而来的类成员

expire	neforce::dns_soa_record
minimum	neforce::dns_soa_record
mname	neforce::dns_soa_record
refresh	neforce::dns_soa_record
retry	neforce::dns_soa_record
rname	neforce::dns_soa_record
serial	neforce::dns_soa_record