Merge pull request rails#23682 from ShikChen/fast_strxor

Improve the performance of string xor operation

Author: spastorino

actionpack/lib/action_controller/metal/request_forgery_protection.rb

@@ -379,7 +379,8 @@ def per_form_csrf_token(session, action_path, method)
 
       def xor_byte_strings(s1, s2)
         s2_bytes = s2.bytes
-        s1.bytes.map.with_index { |c1, i| c1 ^ s2_bytes[i] }.pack('c*')
+        s1.each_byte.with_index { |c1, i| s2_bytes[i] ^= c1 }
+        s2_bytes.pack('C*')
       end
 
       # The form's authenticity parameter. Override to provide your own.