http.head() can return empty unhandled exception

[davenotik]

var response = await http.head('http://v.youku.com/v_show/id_XOTUwODY0NDky.html').catchError(print);
        print(response);

The error is empty. Remove the catchError and it reports as Unhandled Exception:.

[davenotik]

That's the line:

http/lib/src/io_client.dart

Line 76 in 8ecdfac

throw new ClientException(error.message, error.uri);

[nex3]

It looks like the error message will only be empty if an empty error is coming from dart:io. That sounds like a dart:io bug.