Interesting that nobody has mentioned: Warp speed Data Transfer (WDT)[1].

From the readme:

- Warp speed Data Transfer (WDT) is an embeddedable library (and command line tool) aiming to transfer data between 2 systems as fast as possible over multiple TCP paths.

- Goal: Lowest possible total transfer time - to be only hardware limited (disc or network bandwidth not latency) and as efficient as possible (low CPU/memory/resources utilization)

1. https://github.com/facebook/wdt