AA rehash threshold

[Sean Kelly via Digitalmars-d]

On Wednesday, 19 November 2014 at 02:16:36 UTC, Steven 
Schveighoffer wrote:
>
> Well, I just realized that D AA's "load factor" is 4 (see 
> below). That means, for a hash table with 4 buckets, you need 
> to add 17 items to generate a rehash. It also means that you 
> are guaranteed to have one bucket with at least 4 elements on 
> it before a rehash. And that's on an evenly spread hash table. 
> In most cases, we would see buckets with around 8-10 elements.

I'd like this to be configurable once we have the new and 
improved AA implementation.  4 does seem a bit high though.  The 
default max load factor for C++ unordered containers is 1.0.