C#: looking for file stream seek between 2 length

问题:

I would like to copy the partial content of a file using FileStream seek.

1. the actual file stream length of the file = 98764.
2. I want file content between length 200 and 5000

3. If I am doing fileStream.Seek(200, SeekOrigin.Begin), then this give me file content from 200 to 98764, but I want from 200 and 5000.

   public static async Task<HttpResponseMessage> Get()
   {
       using (var fileStream = new FileStream(@"C:\test\tes1.txt", FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
       {
           var actualFileStremSize = fileStream.Length;
   
           //fileStream.Seek(200, SeekOrigin.Begin);
   
           var result = new HttpResponseMessage(HttpStatusCode.OK)
           {
               Content = new StreamContent(fileStream),
           };
   
           using (FileStream fs = new FileStream(@"C:\test\tes1_partial_copy.txt", FileMode.CreateNew, FileAccess.Write))
           {
               await result.Content.CopyToAsync(fs);
           }
   
           return result;
       }
     }
     }
   

Main Method,

     class Program
    {
    static void Main(string[] args)
    {
        Get().Wait();
        Console.ReadLine();
    }

Looking for a solution to get file content between 2 file stream length. Thanks,