Constant mongo_file_center::SETTING_FILE_SIZE_THRESHOLD

pub const SETTING_FILE_SIZE_THRESHOLD: &str = "file_size_threshold";

The name of the file_size_threshold value. When the file size is bigger than file_size_threshold, it should be separate into chunks to store in the COLLECTION_FILES_CHUNKS_NAME collection.

file_size_threshold cannot bigger than 16_770_000.