90% probability for extra loop in copas.send(), copas.sendto()

[Oliver Kroth <oliver.kroth@...>]

Hi,

I am puzzled about a few lines of code in the Copas library functions 
copas.send() and copas.sendto():

    if (math.random(100) > 90) then
      _writing_log[client] = gettime()
      coroutine.yield(client, _writing)
    end

This takes care that send() will give other coroutines a chance to run, 
which is good as otherwise one coroutine may send all the time and no 
other can be resumed.
E.g. you have a web server where one coroutine sends a download, while 
other coroutines wait for incoming connections; these would be blocked 
until the download is finished.

But why is this behaviour coupled to a probabilistic value?

--
Oliver