title: Azure Function Startup issue
body: <p>When deploying an Azure Function project, a null reference exception is thrown when inspecting the deployed functions in the Azure portal.  I can see all three of the functions I deployed, but they all fail to start.  I can run and debug this project just fine on my local computer.</p>
  
  <p>This particular project has three different functions in it.  All three have their own Startup class to handle bootstrapping the function.  I thought that might be an issue (having three startup classes) so I tried consolidating to a single shared startup class, but that doesn't work either.  It doesn't throw the error, but I don't believe they executed either - it's been awhile since I tried that approach.</p>
  
  <p>As I described, there are three functions in a single assembly that's being deployed.  Being relatively new to Azure Functions, what would be best practice here?  Is it recommended to have multiple functions in a single assembly?  Examples I see online show only single functions, I don't think I've seen an example with more than one function per project.  The contents of <code>extensions.json</code> are as follows:</p>
  
  <pre><code>{
    "extensions":[
      { "name": "Startup", "typeName":"My.Functions.ExtractAnalytics.Startup, My.Functions, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"},
      { "name": "Startup", "typeName":"My.Functions.ExtractMetrics.Startup, My.Functions, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"},
      { "name": "Startup", "typeName":"My.Functions.TrimMetricData.Startup, My.Functions, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"}
    ]
  }
  </code></pre>
  
  <p>I thought maybe the <code>name</code> being the same for all three might be a problem, but the types are correct.  When I open the Azure portal and go to inspect the functions, I get a pink popup that shows the following:</p>
  
  <pre><code>Error:
  
  The function runtime is unable to start. My.Functions: Object reference not set to an instance of an object.
  Session Id: 17a68b8fba31433a974b5958f764aeb8
  
  Timestamp: 2019-07-31T17:35:19.743Z
  </code></pre>
  
  <p>None of my logging works, as the runtime seems to fail immediately.</p>