Ethr
Ethr is a comprehensive network measurement tool for TCP, UDP & ICMP
...Ethr takes inspiration from existing open-source network performance tools and builds upon those ideas. For Bandwidth measurement, it is similar to iPerf3, for TCP & UDP traffic. iPerf3 has many more options for doing such as throttled testing, richer feature set, while Ethr has support for multiple threads, which allows it to scale to 1024 or even higher number of connections, multiple clients communication to a single server etc.