Thumbnail doesn't generated

The thumbnail is not being generated. Despite passing FileMessageCreateParams with thumbnailSizes as a parameter when calling chat.apiClient.send() method in sendFileMessage for debugging, the thumbnails in the response are returned as an empty array.

send file message with param with thumbnail size parameter

final params = FileMessageCreateParams.withFile(event.message)
        ..thumbnailSizes = [const Size(300, 300), const Size(50, 50)];

final result =
    handler: (FileMessage message, SendbirdException? e) async {

response of chat.apiClient.send<(UploadResponse)>() inside of sendFileMessage() method (maybe for file upload)

스크린샷 2024-03-13 오후 4.05.28