Global scope is used to launch top-level coroutines which are operating on the whole application lifetime and are not cancelled prematurely. Application code usually should use an application-defined CoroutineScope. Using async or launch on the instance of GlobalScope is highly discouraged.

Noncompliant Code

fun foo() {
    GlobalScope.launch { delay(1_000L) }
}

Compliant Code

val scope = CoroutineScope(Dispatchers.Default)

fun foo() {
    scope.launch { delay(1_000L) }
}

fun onDestroy() {
    scope.cancel()
}