Getting started with message queues
A message queue is nothing more than a queue that we leverage to send ordered messages. A queue works on a First In, First Out (FIFO) basis. If our application runs in a single process, we could use one or more Queue<T> to send messages between our components or a ConcurrentQueue<T> to send messages between threads. Moreover, queues can be managed by an independent program to send messages in a distributed fashion (between applications or microservices).
A distributed message queue can add more or less features to the mix, which is especially true for cloud programs that have to handle failures at more levels than a single server does. One of those features is the dead letter queue, which stores messages that failed some criteria in another queue. For example, if the target queue is full, a message could be sent to the dead letter queue instead.
Many messaging queue protocols exist; some are proprietary, while others are open source...
