Can't recreate a range?

[Casey]

On Thursday, 30 April 2020 at 13:23:25 UTC, Paul Backus wrote:
> Using a default value like this means that it will be shared 
> among all instances of the struct. Instead, you should set 
> `buff = appender!string` in the constructor, so that each 
> struct will have its own appender.

I'll give it a try when I get back to it (fixing lint issues), 
but are you sure that's the issue?  In popFront, I recreate the 
appender.  So, the appender should be clear before the empty 
check after it processes the last of the data from _input.  Still 
a good thing to do as a best practice; I'm just wondering if 
something else is causing an issue and even if initializing the 
appender in the constructor solves the problem, I'd be suspect of 
future issues cropping up.