true if the reference count is greater than 0 and false when
it hits 0. For stateless allocators, it always returns true.
bool decRef() @safe @nogc pureDecreases the reference count of the concrete class that implements this interface. When the reference count is 0, the object self-destructs.
true if the reference count is greater than 0 and false when
it hits 0. For stateless allocators, it always returns true.