The error for a request Host.HTTP will not send.
Host.HTTP reaches the public internet. A request whose host is
loopback, on a private network, link-local or another reserved
address, or whose host does not resolve, comes back as
{:error, %Host.HTTP.BlockedError{}}, and the bang variant raises
it. A redirect is checked the same way, so a public URL that
redirects to a private one is refused at the redirect.
url is the URL refused, without any credentials it carried, and
reason an atom saying why, such as :reserved_address or
:unresolvable_host.
{:error, %Host.HTTP.BlockedError{reason: :reserved_address}} =
Host.HTTP.get("http://localhost:4000/")