Making byLine faster: we should be able to delegate this

[Steven Schveighoffer via Digitalmars-d]

On 3/23/15 9:17 PM, Steven Schveighoffer wrote:
> I re-examined and found something interesting -- assumeSafeAppend
> doesn't cache the block, it only uses the cache if it's ALREADY cached.
>
> So a large chunk of that 35% is the runtime looking up that block info
> in the heap. On my machine, this brings the time from .3 down to .2 s.
>
> I also found a bad memory corruption bug you introduced. I'll make some
> PRs.

https://github.com/D-Programming-Language/druntime/pull/1198
https://github.com/D-Programming-Language/phobos/pull/3098

Note, this doesn't affect performance in this case, as assumeSafeAppend 
isn't used any more.

-Steve