gsutil hangs when the "proxy server return empty response"

I was using gsutil inside a AWS VPC network, and it has no internet IP and the only way to access internet is through PROXY.

When I fired a "gsutil cp" command, it hang and hang for a few hours.

The root cause is the proxy server returns "empty response".

However a timeout / fail-fast would be extremely helpful when gsutil cannot get the connection. Can I make a request that you let gsutil timeout and failed in 100 secs or so if it can not establish the connections ?

Thanks.

gsutil version: 4.12.
python version: Python 2.7.9
Uname:
Linux ip-172-31-70-73 3.14.35-28.38.amzn1.x86_64 #1 SMP Wed Mar 11 22:50:37 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

pip freeze
You are using pip version 6.0.8, however version 7.1.0 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
aws-cfn-bootstrap==1.4
awscli==1.7.22
Babel==0.9.4
backports.ssl-match-hostname==3.4.0.2
bcdoc==0.13.0
boto==2.30.0
botocore==0.103.0
cffi==0.9.2
chardet==2.0.1
cloud-init==0.7.6
colorama==0.2.5
configobj==4.7.2
crcmod==1.7
cryptography==0.8.2
docutils==0.11
ecdsa==0.11
enum34==1.0.4
gcs-oauth2-boto-plugin==1.9
google-api-python-client==1.4.0
google-apitools==0.4.3
gsutil==4.12
httplib2==0.9.1
iniparse==0.3.1
ipython==3.1.0
Jinja2==2.7.2
jmespath==0.6.1
jsonpatch==1.2
jsonpointer==1.0
kitchen==1.1.1
lockfile==0.8
MarkupSafe==0.11
meld3==1.0.2
oauth2client==1.4.7
paramiko==1.15.1
PIL==1.1.6
ply==3.4
protorpc==0.10.0
pyasn1==0.1.7
pyasn1-modules==0.0.5
pycparser==2.12
pycrypto==2.6.1
pycurl==7.19.0
pygpgme==0.3
pyliblzma==0.5.3
pyOpenSSL==0.15.1
pystache==0.5.3
python-daemon==1.5.2
python-dateutil==2.1
python-gflags==2.0
pyxattr==0.5.0
PyYAML==3.10
requests==1.2.3
retry-decorator==1.0.0
rsa==3.1.4
simplejson==3.6.5
six==1.8.0
SocksiPy-branch==1.1
supervisor==3.1.3
uritemplate==0.6
urlgrabber==3.9.1
urllib3==1.8.2
virtualenv==12.0.7
yum-metadata-parser==1.1.4