domain represents the host that this policy applies to. The domain must be IDNA-canonicalized.
HSTSPolicy and related methods will do this for you.
max_age contains the 'max-age' value from the Strict Transport Security header and indicates the time to live of this
policy, in seconds.
expires will be non-%NULL if the policy has been set by the host and hence has an expiry time. If expires is
null, it indicates that the policy is a permanent session policy set by the user agent.
If include_subdomains is true, the Strict Transport Security policy must also be enforced on subdomains of
domain.