MultipartFile.fromBytes constructor
      
      MultipartFile.fromBytes(})
     
    
Creates a new MultipartFile from a byte array.
contentType currently defaults to application/octet-stream, but in the
future may be inferred from filename.
Implementation
factory MultipartFile.fromBytes(String field, List<int> value,
    {String? filename, MediaType? contentType}) {
  var stream = ByteStream.fromBytes(value);
  return MultipartFile(field, stream, value.length,
      filename: filename, contentType: contentType);
}