phobos: What type to use instead of File when doing I/O on streams?

[J.Frank via Digitalmars-d-learn]

On Monday, 9 November 2015 at 18:44:00 UTC, Alex Parrill wrote:
> Ranges are streams. file.byLine(Copy) and byChunk are 
> effectively streams that are ranges.

I might be wrong, but from what I read so far I don't think that 
"ranges are streams":

- Can you read an arbitrary length of bytes from a range? 
(Reading by line in my code was just an example.) The only way I 
see is to make it a byte range. But then reading n bytes would 
result in n calls to popFront(), which is out of the question for 
performance reasons. Is this correct?

- Can you flush() a range?

- Can you use select() on a range?

etc.

(BTW. Where do I find select()/poll() in phobos?)