ChibiOS uses ```gx3_data_buffer``` whereas standard paparazzi is using ```gx3_packet.msg_buf```
The difference is that timing of gx3 isn't consistent, so to have solid 2ms delay between packets, we are buffering them into FIFO. It introduces a little delay (2-6ms depending on the depth of buffer), but it seems to be a better solution than "random" delay between packets (something between 1.5 to 4ms).

That's why it is different.

Maybe eventually we can introduce buffers to standard paparazzi too, but it might not be necessary.