title: use Google Application Default Credentials without json file
body: <p>I have created a console app using c#. I used google cloud speech api. I followed <a href="https://github.com/GoogleCloudPlatform/dotnet-docs-samples/tree/master/speech/api/Recognize" rel="noreferrer">this</a> sample application to create the app.
  To authenticate speech api, I wrote the following code in main method</p>
  
  <pre><code>Environment.SetEnvironmentVariable("GOOGLE_APPLICATION_CREDENTIALS", "path-to-json-file", EnvironmentVariableTarget.Process);
  </code></pre>
  
  <p>Everything works fine. My problem, I have to ship the exe along with the json file. I do not want to expose the json file. How can I embed the json file content in code or authenticate without json file ?
  so that I can only ship the exe to the user.</p>
  
  <p>Any help on this will be appreciated.</p>
  
  <p>Thanks.</p>