pub fn get<K: AsRef<[u8]>>(&self, k: K) -> Option<Option<&InlineArray>> {
        let inner = self.writes.get(k.as_ref())?;
        Some(inner.as_ref())
    }
Get a value if it is present in the `Batch`.
`Some(None)` means it's present as a deletion.
src/tree.rs