how to read some in vibe.d tcpconnection?

[Kagamin via Digitalmars-d-learn]

On Saturday, 7 March 2015 at 02:23:10 UTC, zhmt wrote:
> Hi,I got the right answer in vibe.d forum,here is the link:
>
> http://forum.rejectedsoftware.com/groups/rejectedsoftware.vibed/thread/24403/#post-24416

If that's correct, you can write an extension method for 
InputStream in terms of asio:

ubyte[] readSome(InputStream input, ubyte[] buffer)
{
  	if(input.empty)return null;
  	const len = min(input.leastSize, buffer.length);
  	ubyte[] chunk = buffer[0 .. len];
  	input.read(chunk); // guaranteed to not block now
  	return chunk;
}

And use:
InputStream input=...;
ubyte[256] buffer;
auto chunk = input.readSome(buffer);
if(chunk==null)return done();