//接口中可以组合其它接口，这种方式等效于在接口中添加其它接口的方法  type Reader interface {      read()  }  type Writer interface {      write()  }    //定义上述两个接口的实现类  type MyReadWrite struct{}    func (mrw *MyReadWrite) read() {      fmt.Println("MyReadWrite...read")  }    func (mrw *MyReadWrite) write() {      fmt.Println("MyReadWrite...write")  }    //定义一个接口，组合了上述两个接口  type ReadWriter interface {      Reader      Writer  }    //上述接口等价于：  type ReadWriterV2 interface {      read()      write()  }    //ReadWriter和ReadWriterV2两个接口是等效的，因此可以相互赋值  func interfaceTest0104() {      mrw := &MyReadWrite{}      //mrw对象实现了read()方法和write()方法，因此可以赋值给ReadWriter和ReadWriterV2      var rw1 ReadWriter = mrw      rw1.read()      rw1.write()        fmt.Println("------")      var rw2 ReadWriterV2 = mrw      rw2.read()      rw2.write()        //同时，ReadWriter和ReadWriterV2两个接口对象可以相互赋值      rw1 = rw2      rw2 = rw1  }