Unless a resource is very small, it won't be transmitted in a single atomic unit. The sender will only send a part of it, wait the client to acknowledge having

Unless a resource is very small, it won't be transmitted in a single atomic unit. The sender will only send a part of it, wait the client to acknowledge having received them, and only then send more. That requires a network roundtrip. The larger the resource, the more network roundtrips will be required. If you want to learn more, pretty much any resource on TCP should explain this stuff. Here's something I wrote years ago, the background section should be pretty applicable: https://www.snellman.net/blog/archive/2017-08-19-slow-ps4-downloads/ https://www.snellman.net/blog/archive/2017-08-19-slow-ps4-do...