Add bytesconv pkg for converting strings and slices efficiently

Ref:
golang/go#53003 (comment)

bytesconv/bytesconv.go

@@ -0,0 +1,19 @@
+//go:build go1.20
+
+package bytesconv
+
+import (
+	"unsafe"
+)
+
+// StringToBytes converts string to byte slice without a memory allocation.
+// For more details, see https://github.com/golang/go/issues/53003#issuecomment-1140276077.
+func StringToBytes(s string) []byte {
+	return unsafe.Slice(unsafe.StringData(s), len(s))
+}
+
+// BytesToString converts byte slice to string without a memory allocation.
+// For more details, see https://github.com/golang/go/issues/53003#issuecomment-1140276077.
+func BytesToString(b []byte) string {
+	return unsafe.String(unsafe.SliceData(b), len(b))
+}