StreamReader does not return reamaing and ready data buffer before raise the Exeption

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2017-07-05.20:55:08.161>
labels = ['3.7', 'expert-asyncio']
title = 'StreamReader does not return reamaing and ready data buffer before raise the Exeption'
updated_at = <Date 2018-06-07.09:15:04.407>
user = 'https://github.com/pfreixes'

bugs.python.org fields:

activity = <Date 2018-06-07.09:15:04.407>
actor = 'pfreixes'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['asyncio']
creation = <Date 2017-07-05.20:55:08.161>
creator = 'pfreixes'
dependencies = []
files = []
hgrepos = []
issue_num = 30861
keywords = ['patch']
message_count = 20.0
messages = ['297781', '297783', '297784', '297785', '297787', '297789', '297808', '297842', '297846', '297866', '297873', '297890', '297894', '297898', '297900', '297907', '298532', '298541', '298580', '309261']
nosy_count = 4.0
nosy_names = ['gvanrossum', 'Dima.Tisnek', 'yselivanov', 'pfreixes']
pr_nums = ['2593', '7473']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = None
url = 'https://bugs.python.org/issue30861'
versions = ['Python 3.4', 'Python 3.5', 'Python 3.6', 'Python 3.7']