Associative Arrays need cleanout method or property to help

[Walter Bright]

bearophile wrote:
> A way to know the usage patterns of D AAs is to add instrumentation in
> nonrelease mode, they can save few statistical data once in a while in the
> install directory of D, and then the user can give this little txt file to
> Walter to tune the language :-)

There's no need to tune the language. The implementation and data structure of 
the AAs is completely opaque to the language. The implementation is in aaA.d. 
Feel free to try different implementations in it!