Support custom start-up and clean-up time for VMs (#112)

This pull request implements customizable startup and clean-up time for virtual machine. 
We achieve this by implementing `SimWorkload` chaining and modelling start-up and 
clean-up time using `SimWorkload` as well.

Implements #33

## Implementation Notes :hammer_and_pick:

* Store method parameters in class files
* Add completion parameter to startWorkload
* Provide workload constructors in SimWorkloads 
* Add support for resetting machine context 
* Add support for chaining workloads 
* Use workload chaining for boot delay 
* Model host boot time 
* Do not suspend on guest start 
* Use static logger field 

## Breaking API Changes :warning:

* `SimMachine#startWorkload` now has a third parameter `completion` which is invoked when
   the workload finishes executing (either due to failure or success).
* `SimFlopsWorkload` and `SimRuntimeWorkload` can be instantiated via `SimWorkloads`.

1 files changed, 2 insertions, 2 deletions

diff --git a/opendc-faas/opendc-faas-simulator/src/test/kotlin/org/opendc/faas/simulator/SimFaaSServiceTest.kt b/opendc-faas/opendc-faas-simulator/src/test/kotlin/org/opendc/faas/simulator/SimFaaSServiceTest.kt
index aac54f57..6baee7ea 100644
--- a/opendc-faas/opendc-faas-simulator/src/test/kotlin/org/opendc/faas/simulator/SimFaaSServiceTest.kt
+++ b/opendc-faas/opendc-faas-simulator/src/test/kotlin/org/opendc/faas/simulator/SimFaaSServiceTest.kt
@@ -40,8 +40,8 @@ import org.opendc.simulator.compute.model.MachineModel
 import org.opendc.simulator.compute.model.MemoryUnit
 import org.opendc.simulator.compute.model.ProcessingNode
 import org.opendc.simulator.compute.model.ProcessingUnit
-import org.opendc.simulator.compute.workload.SimRuntimeWorkload
 import org.opendc.simulator.compute.workload.SimWorkload
+import org.opendc.simulator.compute.workload.SimWorkloads
 import org.opendc.simulator.kotlin.runSimulation
 import java.time.Duration
 import java.util.Random
@@ -66,7 +66,7 @@ internal class SimFaaSServiceTest {
     @Test
     fun testSmoke() = runSimulation {
         val random = Random(0)
-        val workload = spyk(object : SimFaaSWorkload, SimWorkload by SimRuntimeWorkload(1000, 1.0) {
+        val workload = spyk(object : SimFaaSWorkload, SimWorkload by SimWorkloads.runtime(1000, 1.0) {
             override suspend fun invoke() {
                 delay(random.nextInt(1000).toLong())
             }