set_minimum_key_length
Description:
Requires the length of the search key for this to be at least length.
Note: 
      
        
    
    GtkEntryCompletion will be removed in GTK 5.
This is useful for long lists, where completing using a small key takes a lot of time and will come up with meaningless results anyway (ie, a too large dataset).
Parameters:
| this | a `GtkEntryCompletion` | 
| length | the minimum length of the key in order to start completing |