Return smoothed drag end velocity with event

rollup.config.js

@@ -0,0 +1,12 @@
+module.exports = {
+  plugins: [
+    require('rollup-plugin-node-resolve')({
+      jsnext: true,
+      main: true,
+      browser: true,
+    }),
+    require('rollup-plugin-commonjs')({
+      include: 'node_modules/**',
+    }),
+  ],
+};