db::Writer::load use size_hint for table.reserve

src/db.rs

@@ -112,6 +112,12 @@ where
     where
         I: Iterator<Item = T>,
     {
+        let hint = iter.size_hint();
+        let hint = std::cmp::max(hint.0, hint.1.unwrap_or(0));
+        if hint > 0 {
+            self.table.reserve(hint);
+        }
+
         for item in iter {
             self.push(item)?;
         }