Page Comparison

...

GenericMongoService(string objectType)

This constructor requires a string description of the Salesforce SObject that it is dealing with e.g. "Contact", "Lead", "Account", etc. The SalesforceSession is not set in the constructor when you only require read/write to MongoDB and rely on the synchronization for reading and writing to Salesforce.

//Create an instance of GenericMongoService to work with Salesforce Lead data using a SalesforceSession
GenericMongoService service = new GenericMongoService(Lead.SFType);