Modifications from upstream for Fuchsia compatibility
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* Use Fuchsia specific random in iperf_util.c
* Shim rusage in iperf_util.c
* Avoid sys/resource.h imports

Testing Changes
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Common commands to ensure that things are working correctly

### Server side: ###
iperf3 -s -4 #Starts a server with IPV4 only

### Client side: ###
iperf3 -c <host ip> #Short 10-second max-rate TCP test
iperf3 -c <host ip> -b 20M #20Mbps 'good-put'
iperf3 -c <host ip> -P 40 #40 streams in parallel, max rate TCP

Also try using the -R option to reverse the data flow