message1: {
                    parallel.syncAt(1)
                    parallel.syncAt(2)
                },
                message3: { parallel.syncAt(3) })
        Dispatch<String> target2 = new DispatchStub(
                message2: {
                    parallel.syncAt(2)
                    parallel.syncAt(3)
                })

        when:
        parallel.run {

        }
        source.onRead { buffer, pos, count ->
            syncAt(1)
            syncAt(2)
            System.arraycopy('aaaa'.bytes, 0, buffer, pos, 4)
            return 4
        }
        source.onRead { buffer, pos, count ->
            syncAt(3)
            System.arraycopy('aa'.bytes, 0, buffer, pos, 2)
            syncAt(4)
            return 2
        }

import "istio.io/istio/pkg/kube"

type Syncer interface {
	WaitUntilSynced(stop <-chan struct{}) bool
	HasSynced() bool
}

var (
	_ Syncer = channelSyncer{}
	_ Syncer = pollSyncer{}
)

type channelSyncer struct {
	name   string
	synced <-chan struct{}
}

func (c channelSyncer) WaitUntilSynced(stop <-chan struct{}) bool {
	return waitForCacheSync(c.name, stop, c.synced)
}

// go work sync

package workcmd

import (
	"cmd/go/internal/base"
	"cmd/go/internal/gover"
	"cmd/go/internal/imports"
	"cmd/go/internal/modload"
	"cmd/go/internal/toolchain"
	"context"

	"golang.org/x/mod/module"
)

var cmdSync = &base.Command{
	UsageLine: "go work sync",
	Short:     "sync workspace build list to modules",
	Long: `Sync syncs the workspace's build list back to the

	return res
}

func (j *join[T]) Register(f func(o Event[T])) Syncer {
	return registerHandlerAsBatched[T](j, f)
}

func (j *join[T]) RegisterBatch(f func(o []Event[T], initialSync bool), runExistingState bool) Syncer {
	sync := multiSyncer{}
	for _, c := range j.collections {
		sync.syncers = append(sync.syncers, c.RegisterBatch(f, runExistingState))
	}
	return sync
}

// nolint: unused // (not true, its to implement an interface)

	// Private markers (only known to cmd/compile).
	SyncPrivate

	SyncFuncExt
	SyncVarExt
	SyncTypeExt
	SyncPragma

	SyncExprList
	SyncExprs
	SyncExpr
	SyncExprType
	SyncAssign
	SyncOp
	SyncFuncLit
	SyncCompLit

	SyncDecl
	SyncFuncBody
	SyncOpenScope
	SyncCloseScope
	SyncCloseAnotherScope
	SyncDeclNames
	SyncDeclName

	SyncStmts
	SyncBlockStmt
	SyncIfStmt

	return maps.Values(s.vals)
}

func (s *staticList[T]) Register(f func(o Event[T])) Syncer {
	return registerHandlerAsBatched(s, f)
}

func (s *staticList[T]) Synced() Syncer {
	return alwaysSynced{}
}

func (s *staticList[T]) RegisterBatch(f func(o []Event[T], initialSync bool), runExistingState bool) Syncer {
	if runExistingState {
		f(slices.Map(s.List(), func(e T) Event[T] {
			return Event[T]{

var _ internalCollection[controllers.Object] = &informer[controllers.Object]{}

func (i *informer[I]) _internalHandler() {}

func (i *informer[I]) Synced() Syncer {
	return channelSyncer{
		name:   i.collectionName,
		synced: i.synced,
	}
}

// nolint: unused // (not true, its to implement an interface)
func (i *informer[I]) dump() {
	i.log.Errorf(">>> BEGIN DUMP")
	for _, obj := range i.inf.List(metav1.NamespaceAll, klabels.Everything()) {

	// using krt), registering directly is expected.
	Register(f func(o Event[T])) Syncer

	// Synced returns a Syncer which can be used to determine if the collection has synced. Once its synced, all dependencies have
	// been processed, and all handlers have been called with the results.
	Synced() Syncer

	// RegisterBatch registers a handler that accepts multiple events at once. This can be useful as an optimization.

 * // filter will not be deleted.
 * task sync(type: Sync) {
 *     from 'source'
 *     into 'dest'
 *     preserve {
 *         include 'extraDir/**'
 *         include 'dir1/**'
 *         exclude 'dir1/extra.txt'
 *     }
 * }
 * </pre>
 */
@DisableCachingByDefault(because = "Not worth caching")
public abstract class Sync extends AbstractCopyTask {