if err != nil {
				return err
			}
		}

		// If the context does not contain the bucket key
		// we must add it for key generation. However,
		// the context must be stored exactly like the
		// client provided it. Therefore, we create a copy
		// of the client provided context and add the bucket
		// key, if not present.
		kmsCtx := kms.Context{}
		for k, v := range cryptoCtx {
			kmsCtx[k] = v
		}

The handler function has this signature.

Sample handler:
```go
    handler :=  func(ctx context.Context, payload []byte, in <-chan []byte, out chan<- []byte) *RemoteErr {
        fmt.Println("Got request with initial payload", p, "from", GetCaller(ctx context.Context))
        fmt.Println("Subroute:", GetSubroute(ctx))
        for {
            select {
            case <-ctx.Done():

			key := msgPath(fmt.Sprintf("%s.%s", bucket, domainName), c.prefixPath)
			key = key + etcdPathSeparator + ip
			ctx, cancel := context.WithTimeout(context.Background(), defaultContextTimeout)
			_, err = c.etcdClient.Put(ctx, key, string(bucketMsg))
			cancel()
			if err != nil {
				ctx, cancel = context.WithTimeout(context.Background(), defaultContextTimeout)
				c.etcdClient.Delete(ctx, key)
				cancel()
				return err
			}
		}

// slice of FileInfo.
func pickValidFileInfo(ctx context.Context, metaArr []FileInfo, modTime time.Time, etag string, quorum int) (FileInfo, error) {
	return findFileInfoInQuorum(ctx, metaArr, modTime, etag, quorum)
}

func writeAllMetadataWithRevert(ctx context.Context, disks []StorageAPI, origbucket, bucket, prefix string, files []FileInfo, quorum int, revert bool) ([]StorageAPI, error) {

        super(messageBuilderFactory, secDispatcher);
    }

    @Override
    protected int doExecute(DefaultEncryptInvoker.LocalContext context) throws Exception {
        String cleartext = context.reader.readLine("Enter the password to encrypt: ", '*');
        context.terminal.writer().println(secDispatcher.encrypt(cleartext, null));
        return OK;
    }

	addedPods   atomic.Int32
	addError    error
	delError    error
}

func (f *fakeZtunnel) Run(ctx context.Context) {
}

func (f *fakeZtunnel) PodDeleted(ctx context.Context, uid string) error {
	f.deletedPods.Add(1)
	return f.delError
}

func (f *fakeZtunnel) PodAdded(ctx context.Context, pod *corev1.Pod, netns Netns) error {
	f.addedPods.Add(1)
	return f.addError
}

// limitations under the License.

package repair

import (
	"context"

	"istio.io/istio/cni/pkg/config"
	"istio.io/istio/cni/pkg/scopes"
	"istio.io/istio/pkg/kube"
)

var repairLog = scopes.CNIAgent

func StartRepair(ctx context.Context, cfg config.RepairConfig) {
	if !cfg.Enabled {
		repairLog.Info("CNI repair controller is disabled")
		return
	}

// this node returns a 404
func proxyHeadToReplicationTarget(ctx context.Context, bucket, object string, rs *HTTPRangeSpec, opts ObjectOptions, proxyTargets *madmin.BucketTargets) (oi ObjectInfo, proxy proxyResult) {
	_, oi, proxy = proxyHeadToRepTarget(ctx, bucket, object, rs, opts, proxyTargets)
	return oi, proxy
}

func scheduleReplication(ctx context.Context, oi ObjectInfo, o ObjectLayer, dsc ReplicateDecision, opType replication.Type) {

	memAvailableMD = NewGaugeMD(memAvailable, "Available memory on the node")
)

// loadMemoryMetrics - `MetricsLoaderFn` for node memory metrics.
func loadMemoryMetrics(ctx context.Context, m MetricValues, c *metricsCache) error {
	memMetrics, err := c.memoryMetrics.Get()
	if err != nil {
		metricsLogIf(ctx, err)
		return err
	}

	m.Set(memTotal, float64(memMetrics.Total))

		"Total number of messages sent since start",
		targetID)
)

// loadAuditMetrics - `MetricsLoaderFn` for audit
// such as failed messages and total messages.
func loadAuditMetrics(_ context.Context, m MetricValues, c *metricsCache) error {
	audit := logger.CurrentStats()
	for id, st := range audit {
		labels := []string{targetID, id}
		m.Set(auditFailedMessages, float64(st.FailedMessages), labels...)