[docs] [issue33082] multiprocessing docs bury very important 'callback=' args

New submission from Chad <millchad@amazon.com>: Callbacks are really important in multiprocessing. Doc writer almost ignores them. ---------- assignee: docs@python components: Documentation messages: 313905 nosy: chadmiller-amzn, docs@python priority: normal severity: normal status: open title: multiprocessing docs bury very important 'callback=' args type: enhancement versions: Python 2.7, Python 3.4, Python 3.5, Python 3.6, Python 3.7, Python 3.8 _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue33082> _______________________________________