* Just to be helpful to developers, give the maximum body length and their body length
* Also point developers to the function to change that value
(I don't think this leaks any sensitive info, because you can always binary search with different request body sizes to find the maximum allowable)
Old code would create a new System.Random generator each time, which
requires going to the system entropy store. New code caches an
mwc-random gen at startup.
