Introduction

Computing has become a world of waiting, and we need support in our programming languages to express wait. The general idea is to suspend (temporarily pause) the current flow and hand execution over to some other flow whenever it reaches a point where we know that we might have to wait for something. This something that we need to wait for could be a network request, a click from a user, a database operation, or even a memory access that is taking too long for us to block.