title: wrap_socket() got an unexpected keyword argument '_context' and deserialize(error)
body: <p>I try to use requests to get a url of file. It works well locally but it doesn't work with nameko.</p>
  
  <p>I tried 3 libs of python3.7. But all has the same error.
  import urllib.request,urllib3,requests</p>
  
  <p>it works well locally like this:</p>
  
  <pre class="lang-py prettyprint-override"><code>import requests
  url = "https://www.python.org/static/img/python-logo.png"
  r = requests.get(url)
  print(r.content)
  </code></pre>
  
  <p>But it can't work with nameko:</p>
  
  <pre class="lang-py prettyprint-override"><code>import requests
  from nameko.web.handlers import http
  
  @http("POST", "/import")
  def testurl(self,request):
      url = "https://www.python.org/static/img/python-logo.png"
      r = requests.get(url)
      print(r.content)
  </code></pre>
  
  <pre class="lang-py prettyprint-override"><code>Traceback (most recent call last):
    File "&lt;console&gt;", line 1, in &lt;module&gt;
    File "/usr/local/lib/python3.7/site-packages/nameko/rpc.py", line 373, in __call__
      return reply.result()
    File "/usr/local/lib/python3.7/site-packages/nameko/rpc.py", line 331, in result
      raise deserialize(error)
  nameko.exceptions.RemoteError: Exception Error on testurl: Cause : wrap_socket() got an unexpected keyword argument '_context'
  </code></pre>