promql/functions.go
func funcMaxOverTime(vals []Value, args Expressions, enh *EvalNodeHelper) Vector {
	return aggrOverTime(vals, enh, func(values []Point) float64 {
		max := values[0].V
		for _, v := range values {
			if v.V > max || math.IsNaN(max) {
				max = v.V
			}
		}
		return max
	})
}
func funcMaxOverTime(vals []Value, args Expressions, enh *EvalNodeHelper) Vector {
	return aggrOverTime(vals, enh, func(values []Point) float64 {
		max := values[0].V
		for _, v := range values {
			if v.V > max || math.IsNaN(max) {
				max = v.V
			}
		}
		return max
	})
}
// === floor(Vector ValueTypeVector) Vector ===
// === max_over_time(Matrix ValueTypeMatrix) Vector ===