Proper Formatting of a JSON and Multiplepart Guzzle Post Request

I have two different guzzle post requests that I am trying to merge (solely because they basically do a united job and should be performed together.

Initially I have my donation data:

'donation' => [
       'web_id' => $donation->web_id,
       'amount' => $donation->amount,
       'type' => $donation->type,
       'date' => $donation->date->format('Y-m-d'),
       'collection_id' => NULL,
       'status_id' => $donation->status_id,
 ],

And then I have my files that go with it, which are basically 2 different PDFs that are enabled or disabled for donors, sometimes they have both. I know the multipart would look something like below, but I'm not sure.

                foreach ($uploadDocs as $doc) {
                        'multipart' => [
                            [
                                'name'     => 'donation_id',
                                'contents' => $donation->web_id,
                            ],
                            [
                                'name'     => 'type_id',
                                'contents' => $doc->type_id',
                            ],
                            [
                                'name'     => 'file',
                                'contents' => fopen($doc->path, 'r'),
                                'headers'  => ['Content-Type' => 'application/pdf'],
                            ],
                        ],
                }

Since I've usually only handled one file at a time and I'm not sure how to merge the first block of code with the second for an appropriate guzzle post request.

I'd appreciate the help! Thanks!

via Chebli Mohamed