new

# File actionpack/lib/action_dispatch/request/session.rb, line 74
      def initialize(by, req, enabled: true)
        @by       = by
        @req      = req
        @delegate = {}
        @loaded   = false
        @exists   = nil # We haven't checked yet.
        @enabled  = enabled
        @id_was = nil
        @id_was_initialized = false
      end