static long calculateForStDefaultArenaBlockSize(long writeBufferSize) {
        long arenaBlockSize = writeBufferSize / 8;

        // Align up to 4k
        final long align = 4 * 1024;
        return ((arenaBlockSize + align - 1) / align) * align;
    }
@Test
    public void testCalculateForStDefaultArenaBlockSize() {
        final long align = 4 * 1024;
        final long writeBufferSize = 64 * 1024 * 1024;
        final long expectArenaBlockSize = writeBufferSize / 8;

        // Normal case test
        assertThat(
                "Arena block size calculation error for normal case",
                ForStMemoryControllerUtils.calculateForStDefaultArenaBlockSize(writeBufferSize),
                is(expectArenaBlockSize));

        // Alignment tests
        assertThat(
                "Arena block size calculation error for alignment case",
                ForStMemoryControllerUtils.calculateForStDefaultArenaBlockSize(writeBufferSize - 1),
                is(expectArenaBlockSize));
        assertThat(
                "Arena block size calculation error for alignment case2",
                ForStMemoryControllerUtils.calculateForStDefaultArenaBlockSize(writeBufferSize + 8),
                is(expectArenaBlockSize + align));
    }