You can pipeline requests on http/1.1. But most servers handle one request at a time, and don't read the next request until the current request's response is finished. (And mainstream browsers don't typically issue pipelined requests on http/1.1, IIRC)
If you have a connection per request, and you need 1000 requests to be 'simultaneous', you've got to get a 1000 packet burst to arrive closely packed, and that's a lot harder than this method (or a similar method suggested in comments of sending unfragmented tcp packets out of order so when the first packet of the sequence is recieved, the rest of the packets are already there)
If you have a connection per request, and you need 1000 requests to be 'simultaneous', you've got to get a 1000 packet burst to arrive closely packed, and that's a lot harder than this method (or a similar method suggested in comments of sending unfragmented tcp packets out of order so when the first packet of the sequence is recieved, the rest of the packets are already there)