Fixed VoidCallback Error

[Harsh223]

Fixed Errors:
Error: Type 'VoidCallback' not found.
../…/utils/downloader_utils.dart:23
final VoidCallback onDone;
^^^^^^^^^^^^
: Error: 'VoidCallback' isn't a type.
../…/utils/downloader_utils.dart:23
final VoidCallback onDone;
^^^^^^^^^^^^

[Harsh223]

@Crdzbird Please accept this pull request or update the code, several apps in production are having issues because of this.

[rohitsangwan01]

@Harsh223 planning to publish as new plugin?? ,or waiting for owner to accept it , i dont really like to use github links in my pubspec

[Harsh223]

@Harsh223 planning to publish as new plugin?? ,or waiting for owner to accept it , i dont really like to use github links in my pubspec

I was actually waiting for him to accept it, but now I guess I'd have to publish it as a standalone one, let me see if the owner allows it.