Added replay protection

src/misc.go

@@ -19,6 +19,13 @@ func min(a uint, b uint) uint {
 	return a
 }
 
+func minUint64(a uint64, b uint64) uint64 {
+	if a > b {
+		return b
+	}
+	return a
+}
+
 func signalSend(c chan struct{}) {
 	select {
 	case c <- struct{}{}: