title: Is there a threadsafe and generic IList<T> in c#?
body: <p>Is <code>List&lt;T&gt;</code> or <code>HashSet&lt;T&gt;</code> or anything else built in threadsafe for addition only?</p>
  
  <p>My question is similar to <a href="https://stackoverflow.com/questions/1278010/threadsafe-and-generic-arraylist-in-c">Threadsafe and generic arraylist?</a> but I'm only looking for safety to cover adding to this list threaded, not removal or reading from it.</p>