Expose same_site instance variable. Fixes #2.

Author: ioquatix

lib/rack/session/abstract/id.rb

@@ -250,7 +250,7 @@ class Persisted
           secure_random: ::SecureRandom
         }.freeze
 
-        attr_reader :key, :default_options, :sid_secure
+        attr_reader :key, :default_options, :sid_secure, :same_site
 
         def initialize(app, options = {})
           @app = app

test/spec_session_pool.rb

@@ -203,6 +203,7 @@
 
   it "passes through same_site option to session pool" do
     pool = Rack::Session::Pool.new(incrementor, same_site: :none)
+    pool.same_site.must_equal :none
     req = Rack::MockRequest.new(pool)
     res = req.get("/")
     res["Set-Cookie"].must_include "SameSite=None"