PHP CURL to upload multiple images in parallel -

i'm using curl wrapper https://github.com/php-curl-class/php-curl-class/blob/master/src/curl/curl.php

to upload images, working if upload photo without multi-curl, when trying upload photos in parallel mode multi-curl, request headers missing part.

 expect: 100-continue  content-type: multipart/form-data; boundary=--------------5a6bd9bcdf53e647                                             

tried debugging , seems whole process of preparing curl, curl child of multi-curl, , file object same.

i assume curlfile modifying curl headers appropriate values, seems lost when using multi-curl ..