/// <summary>
/// Initialises a new instance of the DnsRecord class and specifies the
/// owner name, the resource record class and the TTL of the record.
/// </summary>
/// <param name="owner">The owner name.</param>
/// <param name="type">The class of resource record.</param>
/// <param name="cls">The class of resource record.</param>
/// <param name="ttl">The TTL.</param>
/// <exception cref="System.ArgumentNullException">
/// Thrown when <paramref name="owner"/> is <see langword="null"/>.
/// </exception>
protected DnsRecord(DnsName owner, DnsRecordType type, DnsRecordClass cls, TimeSpan ttl)
{
Guard.NotNull(owner, "owner");
_owner = owner;
_type = type;
_class = cls;
_ttl = ttl;
_expires = DnsClock.Now() + ttl;
}
/// <summary>
/// Returns a value indicating if this resource record is alive.
/// </summary>
public bool IsAlive()
{
return(IsAlive(DnsClock.Now()));
}