on Mac Book Air (OSX 10.7.5) 1.6 GHz Intel Core i5 Memory 4GB
$ go test -bench .
PASS
BenchmarkClosure 100000000 11.5 ns/op
BenchmarkMutexClosure 50000000 35.3 ns/op
BenchmarkAtomicClosure 100000000 17.8 ns/op
BenchmarkChannel 5000000 251 ns/op
ok /path/to/bench 6.747s