Introduction to asynchronous messaging

In our day-to-day life, the concept of communication is fairly straightforward and simple—we call a person and if they receive the call, we can communicate in real time. However, there's another form of communication that is equally important. In this other form, messages cannot be delivered instantly (in real time); rather, once a message is sent, it is stored and is only received when the receiver is able to access it—for instance, voicemails or text messages. If you send a friend a text message and their mobile phone is turned off, they'll still receive the message because the service you're using to send text messages stored it. The first type of messaging is known as synchronous (because it's in real time) and the second type is called asynchronous (because it's not in real time). In this chapter, we'll limit our discussion to asynchronous messaging as it has a greater number of business use cases...