title: Aging Data Structure in C#
body: <p>I want a data structure that will allow querying <em>how many items in last <strong>X</strong> minutes</em>. An item may just be a simple identifier or a more complex data structure, preferably the timestamp of the item will be in the item, rather than stored outside (as a hash or similar, wouldn't want to have problems with multiple items having same timestamp).</p>
  
  <p>So far it seems that with LINQ I could easily filter items with timestamp greater than a given time and aggregate a count. Though I'm hesitant to try to work .NET 3.5 specific stuff into my production environment yet. Are there any other suggestions for a similar data structure?</p>
  
  <p>The other part that I'm interested in is <em>aging</em> old data out, If I'm only going to be asking for counts of items less than 6 hours ago I would like anything older than that to be removed from my data structure because this may be a long-running program.</p>