http: client+server benchmark
baseline runs: (6g, gopher.mtv)
http_test.BenchmarkClientServer 5000 412588 ns/op
http_test.BenchmarkClientServer 5000 403346 ns/op
http_test.BenchmarkClientServer 5000 413936 ns/op
http_test.BenchmarkClientServer 5000 410287 ns/op
http_test.BenchmarkClientServer 5000 388037 ns/op
http_test.BenchmarkClientServer 5000 405545 ns/op
http_test.BenchmarkClientServer 5000 405179 ns/op
http_test.BenchmarkClientServer 5000 413827 ns/op
http_test.BenchmarkClientServer 5000 392723 ns/op
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/
4515155