guzzle Request with POST files
$response = $client->request('POST', 'http://www.example.com/files/post', [
'multipart' => [
[
'name' => 'file_name',
'contents' => fopen('/path/to/file', 'r')
],
[
'name' => 'csv_header',
'contents' => 'First Name, Last Name, Username',
'filename' => 'csv_header.csv'
]
]
]);