Why is `Appender._data` a pointer to its `Data`-store?

[Steven Schveighoffer]

On 10/17/20 12:00 AM, Paul Backus wrote:
> On Saturday, 17 October 2020 at 00:06:31 UTC, Steven Schveighoffer wrote:
>>
>> Appender is ref counted IIRC.
>>
> 
> It's not; it uses the GC.

Oh yeah. In fact, it was me who did that (in 2010!).

My point should have been that the appender is a pImpl to avoid memory 
corruption. If you have multiple copies of an appender, and each has its 
own idea of what the capacity is, then you will get corruption.

See the original bug report here: 
https://issues.dlang.org/show_bug.cgi?id=4681

-Steve