private static void unmapBuffer(@NotNull ByteBuffer buffer) throws Exception {
      if (!buffer.isDirect()) {
        return;
      }
      if (INVOKE_CLEANER_METHOD == null) {
        throw new IllegalStateException("No access to Unsafe.invokeCleaner() -- explicit mapped buffers unmapping is unavailable");
      }

      INVOKE_CLEANER_METHOD.invoke(ReflectionUtil.getUnsafe(), buffer);
      if (LOG_UNMAP_OPERATIONS) {
        LOG.info("Buffer unmapped: " + buffer);
      }
    }
private static void unmapBuffer(@NotNull ByteBuffer buffer)