Log file download via Mavlink is the one that needs the most bandwidth.
It needs typically around 200B TX buffer, and spikes at around 1500B every
10sec, with an average download speed of 230KB/s.
This saves almost 2kb of RAM when using the mavlink shell. 70 matches the
size of the mavlink message. Since the pipe is blocking, a process writing
a lot of data will just wait, data will not be dropped.
The mavlink shell is the only process creating a pipe.
