A FUNCTION that may be started, halted, then resumed is known as a suspend function. ONE of the most important things to remember about the suspend functions is that they can only be invoked from another suspend function or from a coroutine. Suspending functions are MERELY standard Kotlin functions with the suspend modifier ADDED, indicating that they can suspend coroutine execution without blocking the current thread. This means that the code you're looking at may pause execution when it calls a suspending function and restart execution at a later time. However, it makes no mention of what will happen to the present thread in the meantime.

Suspending functions can call any other ordinary functions, but another suspending function is required to suspend the execution. Because a suspending function cannot be called from a REGULAR function, numerous coroutine builders are supplied, allowing you to call a suspending function from a non-suspending scope like launch, async, or runBlocking.

delay() function is an example of suspend function.