Merge "Fix annotation / debugging"

     *

     * @throws IllegalStateException if there is no cached value

     */

    @UnsupportedAppUsage

    public TimestampedValue<Long> getCachedNtpTimeSignal() {

        if (!mHasCache) {

            throw new IllegalStateException("Missing authoritative time source");

        }

        if (LOGD) Log.d(TAG, "currentTimeMillis() cache hit");

        if (LOGD) Log.d(TAG, "getCachedNtpTimeSignal() cache hit");

        return new TimestampedValue<>(mCachedNtpElapsedRealtime, mCachedNtpTime);

    }