set_sexp
Description:
Sets the Search Expression for the cursor.
See: set_sexp_sync.
This asynchronous call is completed with a call to set_sexp.end from the specified callback.
Parameters:
| this | |
| sexp | 
           the new search expression for this  | 
      
| cancellable | 
           a Cancellable to optionally cancel this operation while in progress  | 
      
| callback | 
           callback to call when a result is ready  | 
      
| user_data | 
           user data for the   |