test: replace callback with arrow functions

PR-URL: nodejs#24541 Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>

Author: sreepurnajasti

test/pummel/test-net-throttle.js

@@ -34,7 +34,7 @@ const body = 'C'.repeat(N);
 
 console.log(`start server on port ${common.PORT}`);
 
-const server = net.createServer(function(connection) {
+const server = net.createServer((connection) => {
  connection.write(body.slice(0, part_N));
  connection.write(body.slice(part_N, 2 * part_N));
  assert.strictEqual(connection.write(body.slice(2 * part_N, N)), false);
@@ -44,11 +44,11 @@ const server = net.createServer(function(connection) {
  connection.end();
 });
 
-server.listen(common.PORT, function() {
+server.listen(common.PORT, () => {
  let paused = false;
  const client = net.createConnection(common.PORT);
  client.setEncoding('ascii');
- client.on('data', function(d) {
+ client.on('data', (d) => {
  chars_recved += d.length;
  console.log(`got ${chars_recved}`);
  if (!paused) {
@@ -57,7 +57,7 @@ server.listen(common.PORT, function() {
  paused = true;
  console.log('pause');
  const x = chars_recved;
- setTimeout(function() {
+ setTimeout(() => {
  assert.strictEqual(chars_recved, x);
  client.resume();
  console.log('resume');
@@ -66,14 +66,14 @@ server.listen(common.PORT, function() {
  }
  });
 
- client.on('end', function() {
+ client.on('end', () => {
  server.close();
  client.end();
  });
 });
 
 
-process.on('exit', function() {
+process.on('exit', () => {
  assert.strictEqual(chars_recved, N);
  assert.strictEqual(npauses > 2, true);
 });