close the content stream after writing a response

uhttpsharp/HttpResponse.cs

@@ -106,6 +106,9 @@ namespace uhttpsharp
         {
             ContentStream.Position = 0;
             await ContentStream.CopyToAsync(writer.BaseStream).ConfigureAwait(false);
+
+            // CitizenMP addition
+            ContentStream.Close();
             
             await writer.BaseStream.FlushAsync().ConfigureAwait(false);
         }