Incoming Voice Webhook is getting called twice for the same call

问题

Trying to understand why the incoming voice call webhook is getting called twice.

The phone numbers's voice webhook url is set up to point to my backend and the api endpoint rejects the call right away as follows.

const voiceResponse = new VoiceResponse();
voiceResponse.reject({ reason: 'busy' });
res.type('text/xml');
res.end(voiceResponse.toString());

However, the same call with a different CallSid is pinging the webhook again after a couple of seconds.

来源：https://stackoverflow.com/questions/52157834/incoming-voice-webhook-is-getting-called-twice-for-the-same-call