improve encodeCommand performance, add set-get-delete-string benchmark

benchmark/lib/set-get-delete-string/index.js

@@ -0,0 +1,13 @@
+import yargs from 'yargs';
+import { hideBin } from 'yargs/helpers';
+import { randomBytes } from 'crypto';
+
+const { size } = yargs(hideBin(process.argv))
+    .option('size', {
+        type: 'number',
+        default: 1024,
+        demandOption: true
+    })
+    .parseSync();
+
+export const randomString = randomBytes(size).toString('ascii');