@SuppressWarnings("BooleanMethodIsAlwaysInverted")
    private boolean isGattSegmented(final byte[] pdu) {
        final int gattSar = (pdu[0] & GATT_SAR_MASK) >> SAR_BIT_OFFSET;
        switch (gattSar) {
            case GATT_SAR_START:
            case GATT_SAR_CONTINUATION:
            case GATT_SAR_END:
                return true;
            default:
                return false;
        }
    }
Handles callbacks after writing to characteristics to maintain/update the state machine

@param data written to the peripheral
mesh/src/main/java/no/nordicsemi/android/mesh/MeshManagerApi.java