find_async
Description:
public async GenericArray<unowned Snap> find_async (FindFlags flags, string query, Cancellable? cancellable, out string suggested_currency) throws Error
  
  Asynchronously find snaps in the store.
See find_sync for more information.
Parameters:
| this | a Client. | 
| flags | a set of FindFlags to control how the find is performed. | 
| query | query string to send. | 
| cancellable | a Cancellable or null. | 
| callback | a TaskReadyCallback to call when the request is satisfied. | 
| user_data | the data to pass to callback function. |