Oddly enough, when downloading a file using http or https the file gets corrupted when interruptions occur and do not reliably resume the downloads. Needs a complete deletion and restart.
Too, although I am not an expert at it, I am informed that using an ftp service is the least-demanding useage of system resources one can find, thus its continued popularity.
That’s the beauty of MD5 checksums. I generate MD5 checks for all of my uploads, esp. multipart, and I have the receiver check the data integrity. Admittedly it’s a bit more advanced, but it works really well.