Concurrency is the ability of a program or algorithm to be divided into parts that can be executed out of order without affecting the results. This approach allows for parallel execution in a multi-core environment, which can significantly improve the performance. It's important to understand the difference between concurrency and parallelism. Parallelism assumes that a program is implemented in a concurrent way, but concurrency doesn't mean that the program is executed in parallel.

This chapter will cover the following topics:

• Coroutines
• Sequential operations
• Callback hell
• Thread pools