title: MongoDB fails to connect when multiple hosts are specified in the connection string and one is down
body: <p>I'm using the C# driver to connect to a mongodb replicaset.</p>
  
  <p>The connection string specifies all the hosts that are part of the replicaset:</p>
  
  <pre><code>mongodb://host1:2702,host2:2702,host3:2702,host4:2702,host5:2702/myDb
  </code></pre>
  
  <p>I thought that the idea of a replicaset is to stay connective even when a host goes down.. Not just for speed purposes.</p>
  
  <p>Why is the C# driver tries to connect to every one of the hosts specified in the connection string? I'm ok with it checking which of them is the nearest (because I specified Nearest for the ReadConcern) but when it times out, I want it to ignore that host.</p>
  
  <p>Am I missing anything?</p>