net/http: server optimization; reduce GCs, generate ~half the garbage
There was another bufio.Writer not being reused, found with
GOGC=off and -test.memprofile.
benchmark old ns/op new ns/op delta
BenchmarkServerFakeConnWithKeepAlive 18270 16046 -12.17%
benchmark old allocs new allocs delta
BenchmarkServerFakeConnWithKeepAlive 38 36 -5.26%
benchmark old bytes new bytes delta
BenchmarkServerFakeConnWithKeepAlive 4598 2488 -45.89%
Update #5100
R=golang-dev, gri
CC=golang-dev
https://golang.org/cl/
8038047