lets_build_a_coroutine__subroutine.kt

// a routine:
fun saveUserTasks(userId: Int) {
    val user = loadUser(userId)
    println("user loaded")

    val tasks = loadTasks(user)
    println("tasks loaded")

    saveTasks(tasks)
}

// when called multiple times:
fun main() {
    println("Call #1:")
    saveUserTasks(7)

    println("Call #2:")
    saveUserTasks(7)

    println("Call #3:")
    saveUserTasks(7)

    println("done!")
}

// its like calling it for the first time:
/*
Call #1:
loading a user...
user loaded
loading tasks for provided user...
tasks loaded
saving provided tasks...
Call #2:
loading a user...
user loaded
loading tasks for provided user...
tasks loaded
saving provided tasks...
Call #3:
loading a user...
user loaded
loading tasks for provided user...
tasks loaded
saving provided tasks...
done!
*/