Autosync based on number of unstable ops to prevent journal stalls

src/blockstore.cpp

@@ -68,6 +68,11 @@ uint64_t blockstore_t::get_free_block_count()
     return impl->get_free_block_count();
 }
 
+uint64_t blockstore_t::get_journal_size()
+{
+    return impl->get_journal_size();
+}
+
 uint32_t blockstore_t::get_bitmap_granularity()
 {
     return impl->get_bitmap_granularity();