clib_memcpy (&t0->buffer, b0, sizeof (b0[0]) - sizeof (b0->pre_data));
clib_memcpy (t0->buffer.pre_data, b0->data,
sizeof (t0->buffer.pre_data));
clib_memcpy (&t0->buffer, b0, sizeof (b0[0]) - sizeof (b0->pre_data));
clib_memcpy (t0->buffer.pre_data, b0->data,
sizeof (t0->buffer.pre_data));