improve example benchmark

example/example.js

@@ -18,18 +18,32 @@ console.log(fs.readFileSync(outfile, "utf8"))
 
 // mini benchmark
 if (process.argv.includes("-bench")) {
-  console.log("benchmark start (sampling ~2s of data)")
+  benchmark("bytes", {
+    bytes: true,
+  })
+  benchmark("bytes + onCodeBlock", {
+    bytes: true,
+    onCodeBlock(lang, body) {
+      return null // causes the body to be HTML-escaped & included as is
+    },
+  })
+}
+
+function benchmark(name, options) {
+  console.log(`benchmark start ${name} (sampling ~2s of data)`)
   const timeStart = Date.now()
   const N = 1000, T = 2000
   let ntotal = 0
   while (Date.now() - timeStart < 2000) {
     for (let i = 0; i < N; i++) {
-      global["dont-optimize-away"] = md.parse(source, { bytes: true })
+      global["dont-optimize-away"] = md.parse(source, options)
     }
     ntotal += N
   }
   const timeSpent = Date.now() - timeStart
-  console.log(`benchmark end -- avg parse time: ${((timeSpent / ntotal) * 1000).toFixed(1)}us`)
+  console.log(
+    `benchmark end ${name} -- avg parse time: ` +
+    `${((timeSpent / ntotal) * 1000).toFixed(1)}us`)
 }
 
 function html_escape(str) {