php：如何处理电报机器人请求错误？

I use this: https://telegram-bot-sdk.readme.io/docs

$response = $telegram->sendMessage([
        'chat_id' => '@username', 
        'text' => 'Hello World'
]);

when the username is true, it works. but how can I handle errors? for example when username is wrong or not exist.

1-Some people does not have username!(you can have telegram account with just first name and valid phone number)

2-You cannot send to any valid username(Your bot can just send to users subscribed to your bot (open a chat at least once) and not blocked afterwards)

3-By telegram you can just send to users by chat_id( a large unique number) and not by @username .