The analogue of "fill-pointer" in D

[Kagamin via Digitalmars-d-learn]

On Monday, 18 May 2015 at 16:40:30 UTC, Dennis Ritchie wrote:
> On Monday, 18 May 2015 at 12:49:56 UTC, Kagamin wrote:
>> Filling a buffer is usually done this way: 
>> http://dlang.org/phobos/std_stdio.html#.File.rawRead
>
> Here such example, the task. There is a flow stream, 
> associated, for example, with any socket. It wrote several 
> bytes at a time. To once again not to pull the socket, we start 
> buffer as an array with Phill-pointer. Adding byte array - 
> using the vector-push. When the buffer is stuffed, dump it into 
> the stream and moves pointer to zero. How to do it with the 
> help of readRaw or there writeRaw?

If you want to implement a buffered output stream, it's done 
manually like this: 
https://github.com/D-Programming-Language/phobos/blob/master/std/stream.d#L1711 
or this: 
https://github.com/schveiguy/phobos/blob/new-io3/std/io/text.d#L665