Files as buffered InputRange

[berni]

On Friday, 5 July 2019 at 17:57:39 UTC, Les De Ridder wrote:
> File.byChunk[1] should do the trick.
>
> [1] https://dlang.org/library/std/stdio/file.by_chunk.html

Not sure, if this is, what I'm looking for. I'd like to do 
something like

> buffered_file.map!(a=>2*a).writeln();

When I understand it right, with byChunk I'll have to take care 
about the end of the buffer, myself...