pub fn set_value(&mut self, key: StorageKey, value: StorageValue) {
        match self.state.entry(key.hashed_key()) {
            Entry::Occupied(mut entry) => {
                entry.get_mut().0 = value;
            }
            Entry::Vacant(entry) => {
                self.last_enum_index_set += 1;
                entry.insert((value, self.last_enum_index_set));
            }
        }
    }
Sets the storage `value` at the specified `key`.
core/lib/vm_interface/src/storage/in_memory.rs