通过在多个控制器之间准备segue传递特定键/值

I try to pass data through prepare(for segue) method but I can't get passed data in the ReceiverViewController. I wonder I would better pass the whole instance, don't know if it is possible. I am a newbie on Swift and this is my first try, any advice would be welcome.I try to pass data through prepare(for segue) m