$ go test -v -bench=. -run=none -benchmem .result:
goos: darwin
goarch: amd64
BenchmarkPrintInt2String01-4 10000000 117 ns/op 16 B/op 2 allocs/op
BenchmarkPrintInt2String02-4 30000000 37.3 ns/op 3 B/op 1 allocs/op
BenchmarkPrintInt2String03-4 30000000 38.9 ns/op 3 B/op 1 allocs/op
PASS