title: Convert seconds to hh:mm:ss,fff format in PowerShell
body: <p>I have a string representing a time in seconds and milliseconds. I want to convert it to a string in the format "hh:mm:ss,fff".</p>
  
  <p>My solution still has the flaw that hours less than 10 are shown with one decimal instead of two:</p>
  
  <pre><code>PS&gt; $secs = "7000.6789"
  PS&gt; $ts =  [timespan]::fromseconds($s)
  PS&gt; $res = "$($ts.hours):$($ts.minutes):$($ts.seconds),$($ts.milliseconds)"
  PS&gt; $res
  PS&gt; 1:56:40,679
  </code></pre>
  
  <p>What is the right way to achieve this? I'm sure there is a more elegant way with <code>-f</code> and datetime.</p>