是否有办法将部分PDF字节数组转换成单独的PDF文件?

If I have part of byte array of PDF file(ex: all file byte array size is 10 MB and I have the first 5 MB only), is there any way to save that part of byte array as separate PDF file? Preferably using C#, but any other programming language will be OK If I have part of byte array of PDF file(ex: al