code: async function detectFaces(inputFile) {
    // Make a call to the Vision API to detect the faces
    const request = {image: {source: {filename: inputFile}}};
    const results = await client.faceDetection(request);
    const faces = results[0].faceAnnotations;
    const numFaces = faces.length;
    console.log(`Found ${numFaces} face${numFaces === 1 ? '' : 's'}.`);
    return faces;
  }
docs: Uses the Vision API to detect faces in the given file.
   [START vision_face_detection_tutorial_send_request]