Merge "Remove unnecessary FIXME in close."

    if (mMmapStream != nullptr) {

        // Needs to be explicitly cleared or CTS will fail but it is not clear why.

        mMmapStream.clear();

        // Apparently the above close is asynchronous. An attempt to open a new device

        // right after a close can fail. Also some callbacks may still be in flight!

        // FIXME Make closing synchronous.

        AudioClock::sleepForNanos(100 * AAUDIO_NANOS_PER_MILLISECOND);

    }

}