HSTSPolicy implements HTTP policies, as described by
RFC 6797.
domain represents the host that this policy applies to. The domain must be IDNA-canonicalized. [[email protected]] 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.