cursor is closable

cursor.go

@@ -13,6 +13,10 @@ func (c Cursor[T]) First() *T {
 	return <-c.Chan
 }
 
+func (c Cursor[T]) Close() {
+	defer c.cancelFunc()
+}
+
 func (c Cursor[T]) Next() (*T, bool) {
 	if c.ctx.Err() == nil {
 		value, ok := <-c.Chan