states.gallery

The non-parametric memory-bank approach to appearance: instead of a single filtered embedding, each tracklet stores its last ``K`` matched embeddings. Matching then consults the whole buffer (see :class:`~unitrack.costs.GalleryCost`), so one good past view re-associates an object whose current appearance has drifted. The primary field still holds the most recent embedding, so plain :class:`~unitrack.costs.Cosine` matching also works as a fallback.