Download status callback too slow

If the network environment is not good，download status callback too slow,for example, from now the download progress is 10%, 5 sec later becomes 22%, But during the 5 sec, the progress bar has no change because there there were no callback.

why not callback more faster, eg per seconds or 1000 millseconds...

No file, test, platform, or exact callback interval is named. Start by tracing the download status callback path in the plugin's platform implementation and reproduce the delay under a slow network; done should include a defined callback cadence and a test or reproducible verification showing progress updates arrive accordingly.

Written by the indexing model from the issue text.