Message Broker
Problem statement
Is there anyone to pickup the phone? Otherwise, we need to have a voicemail.
If the server cannot accept the request right away, we need to have a broker to store the message first.
RabbitMQ - AMQP
ZMQ - TCP socket
https://www.educba.com/zeromq-vs-rabbitmq/
Architecture of ZeroMQ
Components of RabbitMQ
Head to Head Comparison Between ZeroMQ vs RabbitMQ
