NewCMSTopkForCardinality creates a new topk sketch where k is the amount of topk we want, and c is the expected total cardinality of the dataset the sketch should be able to handle, including other sketches that we may merge in.

NewCountMinSketch creates a new CMS for a given width and depth.

Topk is a structure that uses a Count Min Sketch and a Min-Heap to track the top k events by frequency.

TopkMatrix is `promql.Value` and `parser.Value`.