type BatchJobPool struct {
	ctx          context.Context
	objLayer     ObjectLayer
	once         sync.Once
	mu           sync.Mutex
	jobCh        chan *BatchJobRequest
	jmu          sync.Mutex // protects jobCancelers
	jobCancelers map[string]context.CancelFunc
	workerKillCh chan struct{}
	workerSize   int
}

var globalBatchJobPool *BatchJobPool