Use retry when getting file sizes

[cuducos]

Here:

chunk/main.go

Line 222 in a27be85

t, err := d.getDownloadSize(ctx, u) // TODO: retry

We could use retry.Do(…) in a similar way we use on the download:

chunk/main.go

Lines 162 to 173 in a27be85

	err := retry.Do(
	func() error {
	b, err := d.downloadFileWithTimeout(ctx, u)
	if err != nil {
	return err
	}
	ch <- b
	return nil
	},
	retry.Attempts(d.MaxRetriesPerChunk),
	retry.MaxDelay(d.WaitBetweenRetries),
	)