private void invokeCloseAction() {
        try {
            closeAction.accept(closeFuture);
        } catch (Throwable cause) {
            closeFuture.completeExceptionally(cause);
        }
    }
Returns the {@link AsyncCloseableSupport} which has been closed already.
core/src/main/java/com/linecorp/armeria/common/util/AsyncCloseableSupport.java