func WithMutable() TreeOption {
	return func(t *Tree) error {
		t.readOnly = false
		return nil
	}
}
The WithMutable option specifies that the tree to be constructed
should allow mutating operations, like writing data, changing file
names, and adding new nodes.
package tree
import (
	"fmt"
	"github.com/nicolagi/muscle/internal/storage"
)
type TreeOption func(*Tree) error