Same functionality as jQuery upload at https://demos.telerik.com/kendo-ui/upload/directoryupload

Add a per-file concurrency option so the Upload component can send multiple chunks of one file simultaneously. The currently available concurrent property only controls whether files upload simultaneously, but does not give the ability to control the concurrency of the chunks in an individual file.

Provide an async mechanism to confirm action before removing files (eg. using Observables).