title: MongoCursor<BsonDocument> converting to List is very slow
body: <pre><code> MongoCollection&lt;BsonDocument&gt; collection = db.GetCollection("TestCollection");
   MongoCursor&lt;BsonDocument&gt; cursor = collection.FindAll();
   List&lt;BsonDocument&gt; list = cursor.toList(); 
  </code></pre>
  
  <p>This is very slow executing.
  MongoCursor converting to a List is very slow, but if I use the following code:</p>
  
  <pre><code>MongoCollection&lt;T&gt; collection = db.GetCollection&lt;T&gt;("TestCollection");
  MongoCursor&lt;T&gt; cursor = collection.findAll();
  List&lt;T&gt; entities = cursor.toList(); 
  </code></pre>
  
  <p>The above code is much faster. Why is MongoCursor converting to a List so slow? I want to use BsonDocument. How can I solve this problem?</p>