before:

BenchmarkLinkNetPipeRTT-4         200000              9763 ns/op            9664 B/op         25 allocs/op
BenchmarkLinkTCPRTT-4             100000             19069 ns/op            9664 B/op         25 allocs/op

after:

BenchmarkLinkNetPipeRTT-4         200000              7872 ns/op            1224 B/op         17 allocs/op
BenchmarkLinkTCPRTT-4             100000             18465 ns/op            1221 B/op         17 allocs/op