Classes for building the index.
            Main indexing classes
| All Types | Classes | Delegates | 
| Icon | Type | Description | 
|---|---|---|
| AsynchronousQueue | 
            Queues and runs operations such as AddDocument asynchronously, use the static methods, not a constructor.
              | |
| DocumentIndex | 
            Represents the document index, and provides functionality for building the index, and adding/removing documents.
              | |
| IndexLockedException | 
            Exception indicating that the index is locked.
              | |
| ReaderExceptionOccurredEventHandler | Specifies a method that handles ReaderExceptionOccured events  | |
| StartUrlCannotBeReadException | 
            Thrown by crawler when the start URL cannot be read, typically because of a network exception.
              | |
| State | 
            The state of the index.
              |