pub fn force_flush(&self) -> Result<()> {
        if !self.inner.state.read().memtable.is_empty() {
            self.inner
                .force_freeze_memtable(&self.inner.state_lock.lock())?;
        }
        if !self.inner.state.read().imm_memtables.is_empty() {
            self.inner.force_flush_next_imm_memtable()?;
        }
        Ok(())
    }
Only call this in test cases due to race conditions
mini-lsm-mvcc/src/lsm_storage.rs