DispatchQueue with concurrency

DispatchQueueConcurrent.swift

private let uploadQueue = DispatchQueue(label: "com.upload.networking",
                                          qos: .utility,
                                   attributes: .concurrent)

//...

if Reachability.checkWiFi() {
   DispatchQueue.main.async { self.appendUploadingView() }
   self.uploadQueue.async { self.uploadViewModel.inputs.uploadAttachment() }
} else {
   self.internetCheckWarnning()
}