func BenchmarkForward(b *testing.B) {
for i := 0; i < b.N; i++ {
var b, f Barrier
b.Forward(&f)
go b.Fall()
<-f.Barrier()
}
}
func BenchmarkForward2(b *testing.B) {
for i := 0; i < b.N; i++ {
var b, f, g Barrier
b.Forward(&f)
f.Forward(&g)
go b.Fall()
<-g.Barrier()
}
}