curl --request POST \
  --url https://api.highwayapi.ai/v3/async/flux-1-kontext-dev \
  --header 'Authorization: <authorization>' \
  --header 'Content-Type: <content-type>' \
  --data '
{
  "prompt": "<string>",
  "images": [
    "<string>"
  ],
  "fast_mode": true,
  "size": "<string>",
  "num_inference_steps": 123,
  "guidance_scale": 123,
  "num_images": 123,
  "seed": 123,
  "output_format": "<string>"
}
'

{
  "task_id": "<string>"
}