docs: @SuppressWarnings("WeakerAccess")
      public synchronized void stop() {
          if (isRunning()) {
              running.set(false);
              MetadataFinder.getInstance().removeMetadataProvider(metadataProvider);
              for (Database database : databases.values()) {
                  //noinspection ResultOfMethodCallIgnored
                  database.sourceFile.delete();
              }
              databases.clear();
          }
      }