title: Search LDAP without exceptions
body: <p>I am writing a performance-sensitive piece of code that will query an LDAP directory where it may be common to not find the object requested (a user or group). </p>
  
  <p>We are using System.DirectoryServices.Protocols.LdapConnection.SendRequest() to submit the query.</p>
  
  <p>If the group/user is not found, SendRequest() throws a DirectoryOperationException.  Since this is performance sensitive, I would really like to avoid exceptions because of the performance hit for handling them.  </p>
  
  <p>Is there an alternate way to query LDAP such that I can get a null/false/empty collection result instead of an exception?  </p>
  
  <p>(I didn't see anything obvious like TrySendRequest, but I am not very familiar with LDAP filter syntax, so I thought perhaps there is something I'm missing)</p>