we want to make sure that we do not hit timeout_idle as long as we stay
below it, but the margin of just 100ms has triggered a false negative.
Double the margin to 200ms...

see with vtest (c4u lines extracted)

**** c4u  Loop #3
**   c4u  === delay 0.3
***  c4u  delaying 0.3 second(s)
**** dT   2.025
**   c4u  === sendhex 0d0a
**** c4u  sendhex|  0d 0a
---- c4u  Write failed: Socket is not connected