'use strict'; const common = require('../common'); const assert = require('assert'); const dgram = require('dgram'); const client = dgram.createSocket('udp4'); const buf = Buffer.allocUnsafe(256); const onMessage = common.mustCall(function(err, bytes) { assert.ifError(err); assert.strictEqual(bytes, buf.length); client.close(); }); client.bind(0, () => client.send(buf, client.address().port, common.localhostIPv4, onMessage));