Implement delete

storage_engine/src/cursor.rs

@@ -247,7 +247,12 @@ impl <'cursor, T> WriteCursor<'cursor, T>
     pub async fn delete_all_entries(&mut self, enable_garbage_collector: bool) -> Result<usize> 
         where T: Encode + Decode + Ord + Send + Sync + Clone
     {
-        let count = todo!();
+        let mut count = 0;
+        while let Some(entry) = self.next_alive().await? {
+            count += 1;
+            self.mark_deleted_at(entry.file_position, false).await?
+        }
+
         if enable_garbage_collector {
             self.attempt_garbage_collection_if_necessary().await?;
         }