Prediction Request

HttpRequest req = new HttpRequest();
req.setMethod('POST');
req.setEndpoint('https://api.einstein.ai/v2/vision/predict');
req.setHeader('content-type', 'multipart/form-data; charset="UTF-8"; boundary="1ff13444ed8140c7a32fc4e6451aa76d"');
req.setHeader('Authorization', 'Bearer <TOKEN>');

req.setHeader('Cache-Control', 'no-cache');
//  Compose the form
string form64 = '';

form64 += HttpFormBuilder.WriteBoundary();
form64 += HttpFormBuilder.WriteBodyParameter('sampleLocation','https://newstechnologystuff.files.wordpress.com/2017/10/18.jpg');
form64 += HttpFormBuilder.WriteBoundary();
form64 += HttpFormBuilder.WriteBodyParameter('modelId', '<MODEL ID>');
form64 += HttpFormBuilder.WriteBoundary(HttpFormBuilder.EndingType.CrLf);
blob formBlob = EncodingUtil.base64Decode(form64);
string contentLength = string.valueOf(formBlob.size());
req.setBodyAsBlob(formBlob);
req.setHeader('Content-Length', contentLength);
req.setTimeout(60*1000);

Http h = new Http();
String resp;
HttpResponse res = h.send(req);
resp = res.getBody();
system.debug(resp);