package two

import "sync"

type sequenceCache struct {
	mu   sync.RWMutex
	data map[sequence]int
}

func newSequenceCache() sequenceCache {
	return sequenceCache{
		data: make(map[sequence]int),
	}
}

func (sc *sequenceCache) upsert(seq sequence, value int) {
	sc.mu.Lock()
	defer sc.mu.Unlock()

	sc.data[seq] += value
}