curl --request POST \
  --url https://api.highwayapi.ai/v3/async/pixverse-v6-extend \
  --header 'Authorization: <authorization>' \
  --header 'Content-Type: <content-type>' \
  --data '
{
  "seed": 123,
  "style": "<string>",
  "video": "<string>",
  "prompt": "<string>",
  "duration": 123,
  "resolution": "<string>",
  "negative_prompt": "<string>",
  "generate_audio_switch": true
}
'

{
  "task_id": "<string>"
}