This is also the reason the self extractors are so easy. A zip file doesn't care what is at the beginning of the file so you can prepend anything you want. No

This is also the reason the self extractors are so easy. A zip file doesn't care what is at the beginning of the file so you can prepend anything you want. Note that streaming is pointless for the examples you give. You definitely want the content signed and integrity checked, and you can't do that until the whole thing is downloaded. If you did decide to start extracting before you have the whole thing then you'd need to ensure no race conditions or avenues of attack from malicious payloads. On a related tale, back when I worked on WAN optimizers I looked at Windows Explorer showing the contents of a zip file (folder view). Writing SMB/CIFS requests by hand it was possible to do so using 5 requests (which means 5 round trips). Explorer in Windows XP used 1,500 requests and Explorer in Vista used 3,000!