title: SSLKEYLOGFILE environment variable doesn't populate any text file
body: <p>My operating system is Windows 10 64 bits. I use the latest versions of Firefox and Chrome.</p>
  
  <p>I want to save the pre-master keys in order to use them with WireShark.</p>
  
  <p>For this, I have found many tutorials that all recommend using the SSLKEYLOGFILE environment variable.</p>
  
  <p>However, no matter the path I put in this variable, no file is being created by Firefox (normal and developer editions) or Chrome. This is true even when I restart those browsers or the operating system. This is also true when I clear the cache on the browsers.</p>
  
  <p>I found an alternative way of setting the SSLKEYLOGFILE variable with Chrome by launching the browser with the following argument:</p>
  
  <pre><code>--ssl-key-log-file=PATH
  </code></pre>
  
  <p>And while this argument does create a log file, it is never populated. It remains completely empty.</p>
  
  <p>What makes this problem even more annoying is that I don't know if there's any debug log that would at least let me know what's happening.</p>
  
  <p>Anyone have ideas on how to solve this issue?</p>