src/server/pkg/hashtree/db.go
func NewFilter(numTrees int64, tree int64) Filter {
	return func(k []byte) bool {
		if pathToTree(k, numTrees) == uint64(tree) {
			return true
		}
		return false
	}
}
func NewFilter(numTrees int64, tree int64) Filter {
	return func(k []byte) bool {
		if pathToTree(k, numTrees) == uint64(tree) {
			return true
		}
		return false
	}
}
// NewFilter creates a filter for a hashtree shard.