@Test
    void readerThreadBlocksWhenBufferFull() {
        def source = stream()
        source.onRead { buffer, pos, count ->
            System.arraycopy('abcdefghij'.bytes, 0, buffer, pos, 10)
            expectLater(1)
            return 10
        }
        source.onRead { buffer, pos, count ->
            shouldBeAt(1)
            return -1
        }

     * Expects that the given tick will be reached at some point in the future. Does not block until the tick has been
     * reached.
     *
     * @param tick The expected clock tick.
     */
    public void expectLater(final int tick) {
        final Thread targetThread = Thread.currentThread();
        LOGGER.debug("Thread {} expecting tick {}", targetThread, tick);
        start(new Runnable() {
            @Override