parameterize what serialization is used in multiprocessing

GitHub fields:

assignee = 'https://github.com/applio'
closed_at = None
created_at = <Date 2016-09-09.20:58:54.395>
labels = ['3.7', 'type-feature', 'library']
title = 'parameterize what serialization is used in multiprocessing'
updated_at = <Date 2019-07-31.16:17:41.253>
user = 'https://github.com/applio'

bugs.python.org fields:

activity = <Date 2019-07-31.16:17:41.253>
actor = 'pierreglaser'
assignee = 'davin'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2016-09-09.20:58:54.395>
creator = 'davin'
dependencies = []
files = ['44511']
hgrepos = []
issue_num = 28053
keywords = ['patch']
message_count = 8.0
messages = ['275437', '275459', '275479', '275486', '293947', '298369', '299434', '314744']
nosy_count = 7.0
nosy_names = ['pitrou', 'python-dev', 'eric.snow', 'davin', 'i3v', 'Will S', 'pablogsal']
pr_nums = ['9959', '15058']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue28053'
versions = ['Python 3.6', 'Python 3.7']