Is there a way to enable this gem in an initializer completely?

F.e. we host our app for different customers, but due to various reasons we want to upgrade manually.

So I would like to enable secure_headers at runtime, like f.e:

if ENV["ENABLE_STRICT_HEADERS"]
  SecureHeaders::Configuration.default do |config|
    ...
  end
else
  SecureHeaders::Configuration.disable! # <= (or something like this)
end

I also don't want to opt out the settings, I completely want to disable secure headers (since sometimes we have set special headers by ourself and we will have to migrate them to secure headers first).