Change Memory stat to include the mem used by direct & mapped byte buffers

[at055612]

e.g.

        ManagementFactory.getPlatformMXBeans(BufferPoolMXBean.class)
                .stream()
                .filter(pool -> "direct".equalsIgnoreCase(pool.getName())
                        || "mapped".equalsIgnoreCase(pool.getName()))

Modify the memory stat to have two new type tag values Direct Buffers Used and Mapped Buffers Used

[at055612]

Fixed in > 7.4-beta.12