i think it's just the usual case diagramactor A sends a message to system
system forwards the message to actor B
actor B responds
but my problem is a little different
Actor A does nothing and the System sends message to A;
Then actor A responds..
Then actor A responds..
爱情是什么颜色的,如果记忆是模糊的
永恒是什么颜色的,如果呼吸是短暂的
快乐是什么颜色的,如果寂寞是灰色的