add bench tool

pkg/handshake/bench.txt

@@ -1,7 +1,7 @@
 goos: linux
 goarch: amd64
-pkg: koti.casa/numenor-labs/dsfx/shared/dnet
+pkg: koti.casa/numenor-labs/dsfx/pkg/handshake
 cpu: Intel(R) Core(TM) Ultra 9 185H
-BenchmarkHandshake-22    	     537	   2179739 ns/op
+BenchmarkHandshake-22    	     530	   2233341 ns/op
 PASS
-ok  	koti.casa/numenor-labs/dsfx/shared/dnet	1.182s
+ok  	koti.casa/numenor-labs/dsfx/pkg/handshake	1.192s

tool/bench/main.go

@@ -0,0 +1,18 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+)
+
+func main() {
+	cmd := exec.Command("go", "test", "-bench=Handshake", "./pkg/handshake/...")
+
+	output, err := cmd.Output()
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Fprint(os.Stdout, string(output))
+}