package observer

func ExampleObserver() {
	subject := NewSubject()
	reader1 := NewReader("reader1")
	reader2 := NewReader("reader2")
	reader3 := NewReader("reader3")
	subject.Attach(reader1)
	subject.Attach(reader2)
	subject.Attach(reader3)

	subject.UpdateContext("observer mode")
	// Output:
	// reader1 receive observer mode
	// reader2 receive observer mode
	// reader3 receive observer mode
}