// Until the value is set all Get() calls will block.
type Singleton[T any] struct {
	v   *T
	set chan struct{}
}

// NewSingleton creates a new unset singleton.
func NewSingleton[T any]() *Singleton[T] {
	return &Singleton[T]{set: make(chan struct{}), v: nil}
}

// Get will return the singleton value.
func (s *Singleton[T]) Get() *T {
	<-s.set
	return s.v
}

		metricsLogIf(ctx, err)
		return err
	}

	m.Set(memTotal, float64(memMetrics.Total))
	m.Set(memUsed, float64(memMetrics.Used))
	usedPerc := float64(memMetrics.Used) * 100 / float64(memMetrics.Total)
	m.Set(memUsedPerc, usedPerc)
	m.Set(memFree, float64(memMetrics.Free))
	m.Set(memBuffers, float64(memMetrics.Buffers))
	m.Set(memCache, float64(memMetrics.Cache))
	m.Set(memShared, float64(memMetrics.Shared))

	// Test Set + Update with Association OpCreate
	assocOp := clause.Association{
		Association: "Pets",
		Type:        clause.OpCreate,
		Set: []clause.Assignment{
			{Column: clause.Column{Name: "name"}, Value: "new-pet"},
		},
	}

	rows, err := gorm.G[User](DB).Where("id = ?", user.ID).Set(assocOp).Update(ctx)
	if err != nil {
		t.Fatalf("Set Update with association failed: %v", err)
	}

	Help = config.HelpKVS{
		config.HelpKV{
			Key:         apiRequestsMax,
			Description: `set the maximum number of concurrent requests (default: auto)`,
			Optional:    true,
			Type:        "number",
		},
		config.HelpKV{
			Key:         apiClusterDeadline,
			Description: `set the deadline for cluster readiness check` + defaultHelpPostfix(apiClusterDeadline),
			Optional:    true,
			Type:        "duration",

#*      *##set ( $spdx = 'BSD-3-Clause' )
#*    *##elseif ( $license.name == "Public Domain" )
#*      *##set ( $spdx = 'Public-Domain' )
#*    *##elseif ( $license.name == "CDDL + GPLv2 with classpath exception" )
#*      *##set ( $spdx = 'CDDL+GPLv2-with-classpath-exception' )
#*    *##else
#*      *### unrecognized license will require analysis to know obligations
#*      *##set ( $spdx = $license )
#*    *##end

	// Currently we only collect S3 API related stats, so we set the "type"
	// label to "s3".

	m.Set(apiRejectedAuthTotal, float64(httpStats.TotalS3RejectedAuth), "type", "s3")
	m.Set(apiRejectedTimestampTotal, float64(httpStats.TotalS3RejectedTime), "type", "s3")
	m.Set(apiRejectedHeaderTotal, float64(httpStats.TotalS3RejectedHeader), "type", "s3")
	m.Set(apiRejectedInvalidTotal, float64(httpStats.TotalS3RejectedInvalid), "type", "s3")

ARGS:
requests_max                    (number)    set the maximum number of concurrent requests (default: 'auto')
cluster_deadline                (duration)  set the deadline for cluster readiness check (default: '10s')
cors_allow_origin               (csv)       set comma separated list of origins allowed for CORS requests (default: '*')

		return errXMLNotWellFormed
	}

	// Both expiration days and date are specified
	if !e.IsDaysNull() && !e.IsDateNull() {
		return errLifecycleInvalidExpiration
	}

	// DeleteAll set without expiration days
	if e.DeleteAll.set && e.IsDaysNull() {
		return errLifecycleInvalidDeleteAll
	}

	return nil
}

					m.Set(bucketReplLastHrFailedBytes, float64(stat.Failed.LastHour.Bytes), labels...)
					m.Set(bucketReplLastHrFailedCount, float64(stat.Failed.LastHour.Count), labels...)
					m.Set(bucketReplLastMinFailedBytes, float64(stat.Failed.LastMinute.Bytes), labels...)
					m.Set(bucketReplLastMinFailedCount, float64(stat.Failed.LastMinute.Count), labels...)

	defaultFormVals := newFormValues()
	defaultFormVals.Set("Bucket", "testbucket")
	defaultFormVals.Set("Content-Type", "image/jpeg")
	defaultFormVals.Set(xhttp.AmzMetaUUID, "14365123651274")
	defaultFormVals.Set("Key", "user/user1/filename/${filename}/myfile.txt")
	defaultFormVals.Set("X-Amz-Credential", "KVGKMDUQ23TCZXTLTHLP/20160727/us-east-1/s3/aws4_request")
	defaultFormVals.Set("X-Amz-Algorithm", "AWS4-HMAC-SHA256")