title: How do you set the readPreference for a single query against mongo using the c# driver
body: <p>I have an application using a number of different mongo databases and 99% of the time it needs to read from the primary of the replica set but I have a couple reporting queries that pull back a lot of data and are not covered by indexes and I would like them to run against a secondary.  Is there any way to specify for a single query that it should have a read preference of secondary.  I am wanting to avoid having more connection strings as I already have near a dozen in the application.</p>