Returns the largest ATT write value, at most maxWrite bytes, that exactly
fills whole link-layer packets (251k - 7 bytes: 244, 495, ...). A write
that overruns a packet boundary by a few bytes spends a whole extra packet
of airtime on them. Returns maxWrite when not even one packet fits.
Returns the largest ATT write value, at most maxWrite bytes, that exactly fills whole link-layer packets (251k - 7 bytes: 244, 495, ...). A write that overruns a packet boundary by a few bytes spends a whole extra packet of airtime on them. Returns maxWrite when not even one packet fits.