title: Calling map_async within a thread not working
body: <p>using the multiprocessing pool in python
  This is what I'm trying to do:</p>
  
  <pre><code>def do_task(data):
     print "Executing: " + data
     return data
  
  def do_something(data):
     print "Starting do_something"
     result2 = pool.map_async(do_task, ["AA","BB"])  
     print "before get"
     result2.get()
     print "after get"
     return data
  
  def main():
      pool = Pool(processes=4)             
      result = pool.apply_async(do_something, "A")  
      print result.get()
  </code></pre>
  
  <p>But it doesn't work here the output:</p>
  
  <pre><code>Starting do_something
  before get
  </code></pre>
  
  <p>it stays stuck here and do_task is never called. Ca someone explain me why?
  Thank you</p>