RabbitMQ Data Transfer
In RabbitMQ, the consumer doesn't pick up messages from the queue like I assumed.
When the consumer starts, it connects to the broker over a TCP connection. When there is a message for the consumer, the broker pushes it over that same TCP session.
RabbitMQ supports both push and pull. Push is the default.
Pull is supported but not recommended. For both, the consumer must start the TCP session. The broker starts no sessions.
Multiple Consumers
With many consumers, the broker keeps track. It pushes messages to the consumer TCP connections in a round-robin way.
Producers don't need sessions
Producers need not keep a TCP session open. They can start a session, send messages to the broker, and close it.
An active TCP session need not be maintained using heartbeat or pings.
Topic Exchange
Necessary when a same message must be sent to multiple consumers based on conditions (routing-key).