title: Parallel download of blobs from GCS gives SSL error
body: <p>I am trying to read data from Google Cloud Storage in parallel using <code>multiprocessing</code> in python, but I am keep getting the following SSL error:</p>
  
  <pre><code>OpenSSL.SSL.Error: [('SSL routines', 'ssl3_read_bytes', 'sslv3 alert bad record mac')]
  </code></pre>
  
  <p>Here is my minimal example:</p>
  
  <pre><code>client_storage = storage.Client.from_service_account_json(ACCOUNT_JSON)
  bucket = client_storage.get_bucket(MY_BUCKET)
  
  def fun(blobid):
     blob = bucket.get_blob(blobid)
     res = blob.download_as_string()
  
     pass
  
  import multiprocessing
  
  num_proc = 4
  
  with multiprocessing.Pool(processes=num_proc) as pool:
     pool.map(fun, list_if_filenames )
  </code></pre>
  
  <p>I need to download and process the data from GCS in parallel (up to 100 processes) to speed up the computation. If that method is not allowed do you know of any other solution?</p>