brewkit.rb changes ENV destructively, so lets not do that everytime a formula
is required. Now it's possible for other tools to require a formula
description without worrying about side-effects.
Iperf was developed by NLANR/DAST as a modern alternative for measuring
maximum TCP and UDP bandwidth performance. Iperf allows the tuning of various
parameters and UDP characteristics. Iperf reports bandwidth, delay jitter,
datagram loss.