// Send a text message
let promise = TUIChatService.sendTextMessage(
{ 
   payload: {   text: 'Hello world!' }
},
{
  // If the recipient is offline, the message is stored for roaming and an offline push notification is sent when the recipient's app is in the background or its process has been killed. You can customize the title and content of the offline push notification.
   offlinePushInfo: {
     androidInfo: { // Android push configuration
        sound: 'private_ring.mp3', // Android custom ringtone
        XiaoMiChannelID: '', // Required on Xiaomi devices running Android 8.0 or later
        FCMChannelID: '', // Required to configure notification sounds for FCM on Google devices running Android 8.0 or later
        OPPOChannelID: '', // Required on OPPO devices
      },
      apnsInfo: { // APNs push configuration
     // apnsInfo.sound = TUIChatEngine.TYPES.IOS_OFFLINE_PUSH_NO_SOUND: no sound is played when the notification is received.
     // apnsInfo.sound = TUIChatEngine.TYPES.IOS_OFFLINE_PUSH_DEFAULT_SOUND: the system sound is played when the notification is received.
        sound: 'private_ring.caf', // iOS custom ringtone
      }
   }
}
);
promise.catch((error) => { 
    // If an exception occurs, catch it with promise.catch for error handling.
});