task slow { doLast { ${server.callFromBuild('sync')} } }
"""
        def sync = server.expectAndBlock('sync')
        withConnection { connection ->
            connection.model(GradleBuild).setJvmArguments(buildJvmArguments).get()
        }
        toolingApi.daemons.daemon.assertIdle()

        def build = daemonExecutor().withTasks("slow").start()
        sync.waitForAllPendingCalls()

package main

import (
	"fmt"
	"log"
	"net"
	"os"
	"runtime"
	"runtime/trace"
	"sync"
	"syscall"
	"time"
)

func main() {
	if err := trace.Start(os.Stdout); err != nil {
		log.Fatal(err)
	}

	// checkExecutionTimes relies on this.
	var wg sync.WaitGroup
	wg.Add(2)
	go cpu10(&wg)
	go cpu20(&wg)
	wg.Wait()

	// checkHeapMetrics relies on this.

)

func TestSynchronous(t *testing.T) {
	// Root is always run sync.
	newLevels().
		// Level 1: bf=5(sync)
		Add(5, false).
		// Level 2: bf=2(sync)
		Add(2, false).
		// Level 3: bf=2(sync)
		Add(2, false).
		Build().
		Run(t)
}

func TestParallel(t *testing.T) {
	// Root is always run sync.
	newLevels().
		// Level 1: bf=20(parallel)
		Add(20, true).
		// Level 2: bf=5(parallel)

package once

import (
	"context"
	"sync"
	"sync/atomic"
)

// Inspired from Golang sync.Once but it is only marked
// initialized when the provided function returns nil.

// Init represents the structure.
type Init struct {
	done uint32
	m    sync.Mutex
}

// Do is similar to sync.Once.Do - makes one successful
// call to the function. ie, it invokes the function

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package target

import (
	"sync"
	"sync/atomic"
)

// Inspired from Golang sync.Once but it is only marked
// initialized when the provided function returns nil.

type lazyInit struct {
	done uint32
	m    sync.Mutex
}

func (l *lazyInit) Do(f func() error) error {
	if atomic.LoadUint32(&l.done) == 0 {
		return l.doSlow(f)

	}

	fs.BoolVar(&o.DisableAttachDetachReconcilerSync, "disable-attach-detach-reconcile-sync", false, "Disable volume attach detach reconciler sync. Disabling this may cause volumes to be mismatched with pods. Use wisely.")

			StabilityLevel: metrics.ALPHA,
		},
		[]string{"status", "apiserver_id_hash"},
	)
)

var registerMetrics sync.Once
var hashPool *sync.Pool

func RegisterMetrics() {
	registerMetrics.Do(func() {
		hashPool = &sync.Pool{
			New: func() interface{} {
				return sha256.New()
			},
		}
		legacyregistry.MustRegister(authorizationConfigAutomaticReloadsTotal)

		cidr, _ := cidrset.NewCIDRSet(clusterCIDRRange, 24)
		tc.fake.logger = logger
		sync := New(&tc.fake, &tc.fake, &tc.fake, tc.mode, "node1", cidr)
		doneChan := make(chan struct{})

		// Do a single step of the loop.
		go sync.Loop(logger, doneChan)
		sync.Update(tc.node)
		close(sync.opChan)
		<-doneChan
		tc.fake.dumpTrace()

		if !reflect.DeepEqual(tc.fake.events, tc.events) {

        given:
        goodCode()
        def sync = server.expectAndBlock('sync')

        when:
        def result = []
        withConnection { ProjectConnection connection ->
            connection.newBuild().forTasks('test').addProgressListener({ ProgressEvent event ->
                result << event
                if (!killed) {
                    sync.waitForAllPendingCalls()
                    sync.releaseAll()

    def "client can cancel during execution of a continuous build"() {
        given:
        setupCancellationBuild()
        def sync = server.expectAndBlock('sync')

        when:
        runBuild {
            sync.waitForAllPendingCalls()
            cancellationTokenSource.cancel()
            sync.releaseAll()
        }

        then:
        assert buildResult.failure instanceof BuildCancelledException