Initializes the spider so the next GetNextDoc call will return the first document.

true if the data source was initialized successfully, or false if the data could not be accessed.

The dtSearch Engine will call Rewind at the start of the index update to initialize the data source. The Spider will then return true if the data source was initialized successfully, or false if it could not access any pages to index.  

All of this happens automatically when you attach the HttpDataSource to the IndexJob and execute it, so there is no need for your code to interact with Rewind().