docs: public CompletableFuture<CloseResponse> close(CloseRequest request) {
      ComposableFuture<CloseResponse> future = new ComposableFuture<>();
      threadContext.execute(() -> {
        PrimaryBackupSession session = sessions.get(request.session());
        if (session != null) {
          role.close(session).whenComplete((result, error) -> {
            if (error == null) {
              future.complete(CloseResponse.ok());
            } else {
              future.complete(CloseResponse.error());
            }
          });
        } else {
          future.complete(CloseResponse.error());
        }
      });
      return future;
    }