code: @Override
      public void close() {
          for (T unusedInstance; (unusedInstance = unusedInstances.poll()) != null;) {
              if (unusedInstance instanceof AutoCloseable) {
                  try {
                      ((AutoCloseable) unusedInstance).close();
                  } catch (final Exception e) {
                      // Ignore
                  }
              }
          }
      }
docs: Free all unused instances. Calls {@link AutoCloseable#close()} on any unused instances that implement
  {@link AutoCloseable}.
  
  <p>
  The {@link Recycler} may continue to be used to acquire new instances after calling this close method, and
  then this close method may be called again in future, i.e. the effect of calling this method is to simply
  clear out the recycler of unused instances, closing any {@link AutoCloseable} instances.