Reports already downloaded bytes as downloaded

[cuducos]

As far as I got, we just send a DownloadStatus updating the total downloaded size if we try to download a chunk. This means that for chunks downloaded in previous runs, their bytes would be missing from the total count (i.e. DownloadedFileBytes). I am not sure whether this is intended or not.

• On the one hand, they are not downloaded in this run, so they might not be reported as they would mean something downloaded in another moment/context
• On the other hand, if we don't report them, the download will complete successfully, but DownloadedFileBytes will not match the expected file size in the last status

Since most of download managers count the bytes downloaded previously towards the total bytes downloaded, I suggest we add these lines. Any ideas? Any ideas about how to test that behavior?

[danielfireman]

I like the idea of reporting the previously downloaded bytes.

About the test, one possible way is get inspiration from TestDownload_Retry idea, but add a check for the first Status received after the timeout or error. How does that sound? Am I missing something?

[cuducos]

Awesome! Nice inspiration indeed : )