anchor.diff:  inform_dist* inform_dist_infer(int const *events, size_t n);
   ----
   Infer a distribution from a collection of observed events.
  +
  +*Examples:*
  +[source,c]
  +----
  +inform_dist *dist = inform_dist_infer((int[]){0,0,1,0,1}, 5);
  +assert(dist);
  +// dist->histogram ~ {3,2}
  +inform_dist_free(dist);
  +----
  +[source,c]
  +----
  +inform_dist *dist = inform_dist_infer((int[]){0,0,1,0,1,2,2,1}, 8);
  +// dist->histogram ~ {3,3,2}
  +inform_dist_free(dist);
  +----
   ****
   
   ****
  
positive.code:         double tol);
  ----
  Approximate a given probability distribution to a given tolerance.
  ****
  
  ****
  
negative.code: inform_dist* inform_dist_create(uint32_t const *data, size_t n);
  ----
  Create a distribution from an underlying histogram.
  
  *Examples:*
  [source,c]
  ----
  inform_dist *dist = inform_dist_create((int[5]){0,1,2,3,4}, 5);
  assert(dist);
  // dist->histogram ~ {0,1,2,3,4}
  inform_dist_free(dist);
  ----
  ****
  
  ****
  