Understanding coroutine contexts and jobs

In this section, you will learn about coroutine contexts and jobs. Coroutines run in a coroutine context. A job is the context of the coroutine that allows you to manage the coroutine’s execution.

Coroutine contexts

Each coroutine runs in a coroutine context. A coroutine context is a collection of elements for the coroutines that specifies how the coroutine should run. A coroutine scope has a default coroutine context; if it’s empty, it will have an EmptyCoroutineContext.

When you create a CoroutineScope or use a coroutine builder, you can pass in a CoroutineContext. In the previous examples, we were passing a dispatcher:

CoroutineScope(Dispatchers.IO) {

    …

}

viewModelScope.launch(Dispatchers.Default) { ... }

The preceding example shows how to pass a dispatcher in the CoroutineScope function or in the coroutine builder.

What you’re passing in these functions is a...