import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;

import org.apache.maven.api.model.Model;

/**
 * Holds all Models that are known to the reactor. This allows the project builder to resolve imported Models from the
 * reactor when building another project's effective model.
 *
 */
class ReactorModelPool {
    private final Map<GAKey, Set<Model>> modelsByGa = new ConcurrentHashMap<>();

 */
public interface Builder {
    //
    // Be nice to whittle this down to Session, maybe add task segments to the session. The session really is
    // the place to store reactor related information.
    //
    void build(
            MavenSession session,
            ReactorContext reactorContext,
            ProjectBuildList projectBuilds,
            List<TaskSegment> taskSegments,

    //
    // 4) Create MavenSession.
    //
    // 5) Execute AbstractLifecycleParticipant.afterSessionStart(session)
    //
    // 6) Get reactor projects looking for general POM errors
    //
    // 7) Create ProjectDependencyGraph using trimming which takes into account --projects and reactor mode.
    // This ensures that the projects passed into the ReactorReader are only those specified.
    //

        private final static int[] DELAYS = [2, 3, 5, 8, 13, 21, 34, 55]

        private final static boolean LOG = false
        private final static Map<String, Integer> FACTORS = [
            'jar': 10,
            'xml': 3,
            'pom': 3
        ].withDefault { 1 }

        private final AtomicInteger concurrency = new AtomicInteger()

        @Override

				// Create a volume before provisionClaimOperation starts.
				// This similates a parallel controller provisioning the volume.
				volume := newVolume("pvc-uid11-7", "1Gi", "uid11-7", "claim11-7", v1.VolumeBound, v1.PersistentVolumeReclaimDelete, classGold, volume.AnnBoundByController, volume.AnnDynamicallyProvisioned)
				reactor.AddVolume(volume)
			}),
		},
		{

                .desc(
                        "Resume reactor from the last failed project, using the resume.properties file in the build directory")
                .build());
        options.addOption(Option.builder(RESUME_FROM)
                .longOpt("resume-from")
                .hasArg()
                .desc("Resume reactor from specified project")
                .build());

The purpose of running most builds though is to process some new changes.
The structure of the software being built (how many modules are there, how independent are its parts etc.), and the nature of the changes themselves ("big refactor in the core of the system" vs. "small change to a unit test" etc.) strongly influence the performance gains delivered by the build cache.

                // whereas console failure logging based on the _thrown exception_ happens up outside session scope. It would be better to refactor so that a result can be returned from here
                throw UncheckedException.throwAsUncheckedException(t);
            } else {

                // whereas console failure logging based on the _thrown exception_ happens up outside session scope. It would be better to refactor so that a result can be returned from here
                throw UncheckedException.throwAsUncheckedException(t);
            } else {

	rootCmd.SetOut(&out)
	rootCmd.SetErr(&err)
	// istioctl will overwrite logs which we don't want.
	// It happens to do this via PersistentPreRunE, which we can disable.
	// We add an additional check in case someone refactors this away, to ensure we don't wipe out non-logging code.
	if fmt.Sprintf("%p", rootCmd.PersistentPreRunE) != fmt.Sprintf("%p", cmd.ConfigureLogging) {
		log.Fatalf("istioctl PersistentPreRunE is not configuring logging")
	}