Add remove unused script

remove-unused.sh

@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+
+set -e -o pipefail
+
+function remove_unused() {
+  git rm -rf --ignore-unmatch \
+    .github \
+    tests \
+    *_test.go \
+    **/*_test.go \
+    conn/bindtest \
+    tun/netstack \
+    tun/tuntest \
+    tun/testdata \
+    main*.go \
+    *.md
+}
+
+remove_unused
+remove_unused
+
+go mod tidy
+git commit -a -m "Remove unused"