Which of these 2 functions is fastest?

foo_test.go

package bench

import "testing"

var fooMap = map[string]int{"a": 1, "b": 2}

func Foo1(s string) int { 
	return fooMap[s]
}

func Foo2(s string) int {
	switch s {
	case "a":
		return 1
	case "b":
		return 2
	default:
		return 0
	}
}

func BenchmarkFoo1(b *testing.B) {
	for i := 0; i < b.N; i++ {
		Sink += Foo1(A)
		Sink += Foo1(B)
	}
}

func BenchmarkFoo2(b *testing.B) {
	for i := 0; i < b.N; i++ {
		Sink += Foo2(A)
		Sink += Foo2(B)
	}
}

//
// Exported variables (won't be optimized away, or constant-propagated)
//

var Sink int
var A, B = "a", "b"

% go test -bench=. -v
goos: darwin
goarch: arm64
BenchmarkFoo1
BenchmarkFoo1-10    	152906709	         7.861 ns/op
BenchmarkFoo2
BenchmarkFoo2-10    	508370997	         2.368 ns/op