I want to record audio from Discord's audio channel in Node.js.

const { Client, GatewayIntentBits, Partials, } = require('discord.js');
const { joinVoiceChannel, EndBehaviorType  } = require('@discordjs/voice');
const fs = require('node:fs');
const stream = require('node:stream');
const client = new Client({
  intents: Object.values(GatewayIntentBits),
  partials: [Partials.Message, Partials.Channel, Partials.Reaction], rest: 60000
});
const prefix = '!';
client.once('ready', () => {
  console.log(`Logged in as ${client.user.tag}`);
});

client.on('messageCreate', async (message) => {
  if (message.content.startsWith(prefix + 'join')) {
    const voiceChannel = message.member?.voice.channel;
    if (!voiceChannel) {
      return message.reply('このコマンドを使用するには、音声チャンネルに参加している必要があります。');
    }

    const connection = joinVoiceChannel({
      channelId: voiceChannel.id,
      guildId: voiceChannel.guild.id,
      adapterCreator: voiceChannel.guild.voiceAdapterCreator,
    });
    connection.receiver.speaking.on('start', (userId) => {
      const audio = connection.receiver.subscribe(userId, {
        end: {
          behavior: EndBehaviorType.AfterSilence,
          duration: 100,
        },
      });
      var filename = './rec/'.concat(Date.now(), '-').concat(userId, '.pcm');
      var out = fs.createWriteStream(filename);
      stream.pipeline(audio, out, function (err) {
        if (err) {
          console.warn(`❌ Error recording file ${filename} - ${err.message}`);
        } else {
          console.log(`✅ Recorded ${filename}`);
        }
      });
    });
  }
});