Laravel resource ignoring given fields

I'm trying to convert a given API response in something easy to work with.

This is what I have so far:

Controller:

public function drive()
{
    $optParams = [
        'corpora' => 'drive',
        'driveId' => env('GOOGLE_DRIVE_ID'),
        'includeItemsFromAllDrives' => true,
        'supportsAllDrives' => true,
        'fields' => 'files(*)'
    ];

    $results = $this->googleDrive->files->listFiles($optParams);
    $data = collect($results);
    $collection = new FileCollection($data);
    dd($collection);

    return 'Hi!';
}

FileCollection resource:

public function toArray($request)
{
    return [
        'data' => $this->collection,
        'meta' => ['files_count' => $this->collection->count()],
    ];
}

File resource:

public function toArray($request)
{
    return [
        'name' => $this->resource['name'],
        'mime' => $this->resource['mimeType'],
        'parents' => $this->resource['parents'],
        'version' => $this->resource['version'],
        'webDownloadLink' => $this->resource['webContentLink'],
        'webLink' => $this->resource['webViewLink'],
        'modified_at' => $this->resource['modifiedTime'],
        'size' => $this->resource['size']
    ];
}

This is the result I'm getting:

FileCollection {#223 ▼
  +collects: null
  +collection: Collection {#243 ▶}
  +resource: Collection {#243 ▼
    #items: array:2 [▼
      0 => File {#224 ▼
        +resource: Google_Service_Drive_DriveFile {#279 ▶}
        +with: []
        +additional: []
      }
      1 => File {#263 ▼
        +resource: Google_Service_Drive_DriveFile {#269 ▶}
        +with: []
        +additional: []
      }
    ]
  }
  +with: []
  +additional: []
}

So as you can see the types of resources are correct, but for some reason the 'meta' in the FileCollection isn't there, nor are the fields in the File resource. All fields are available, like 30+.

Am I missing something here?

via Chebli Mohamed