title: Warning message from tika python module using the unpack method
body: <p>I'm currently using <code>tika</code> to extract the text from pdf files. I found a very fast method within the <code>tika</code> module. This method is called <code>unpack</code>. 
  This is my code:</p>
  
  <pre><code>from tika import unpack
  
  text = unpack.from_file('example.pdf')['content']
  </code></pre>
  
  <p>However, once in a while (not always!) I get this warning:</p>
  
  <pre><code>2018-11-02 15:30:25,533 [MainThread ] [WARNI] Failed to see startup log message; retrying...
  </code></pre>
  
  <p>After retrying the code starts to work. However, I don't understand the warning and also it takes time to retry.
  Anyone has an idea why I get this warning?</p>
  
  <p>This is the github page:
  <a href="https://github.com/chrismattmann/tika-python" rel="noreferrer">https://github.com/chrismattmann/tika-python</a></p>