asp code Response.Flush() working fine on IE8 but not on IE11

hi,

I've been encountering problem when downloading excel file from my system.

and the root of the problem is my asp code = Response.flush()

on IE8 this code worked perfectly but since my IE been upgraded to IE11 

"***file can't be downloaded" error always appearing.

when I change the Response.flush() to Response.end() the download process work perfectly fine.

I want to know the reason why Response.flush causing download problem on IE11.

can somebody help me?

thank you.