module ActiveSupport::MessagePack::Extensions

def write_object(object, packer)
  if object.class.respond_to?(:from_msgpack_ext)
    packer.write(LOAD_WITH_MSGPACK_EXT)
    write_class(object.class, packer)
    packer.write(object.to_msgpack_ext)
  elsif object.class.respond_to?(:json_create)
    packer.write(LOAD_WITH_JSON_CREATE)
    write_class(object.class, packer)
    packer.write(object.as_json)
  else
    raise_unserializable(object)
  end
end