Throughout the previous chapters of the book, we have looked at how actors behave and how we can easily create distributed, concurrent and failure-tolerant applications by combining them. Also, actors can be used to create more complex libraries. Two good examples are Akka Streams and Akka HTTP. However, many other use cases require the use of actors themselves. 

In this chapter, we will go through different actor pattern recipes to showcase useful common scenarios. We will learn important concepts in order to prevent mailbox message overflow using a Master Slave work pattern, pulling and balancing the workload across a set of actors. We will revisit how to stop children actors in an orderly manner by creating and an elegant way to identify when all actors in an actor system are stopped to terminate it, which might be handy in dynamic environments.

We will also explain the convenient API Akka provided to easily create Finite State Machines just by providing a set of states and...