Augh, nevermind, it's immutable TimeZone

[FeepingCreature via Digitalmars-d]

Augh, nevermind, it's immutable TimeZone. TimeZone needs to be 
immutable for some reason, so it needs Rebindable, so SysTime has 
opAssign anyways, because there's no native way to specify a 
tailconst for class references.

Augh.
Maybe it's finally time to write an emplace-based version of 
Nullable?