delete_cookie
Description:
[ Version ( since = "2.20" ) ]
public async bool delete_cookie (Cookie cookie, Cancellable? cancellable = null) throws Error
  public async bool delete_cookie (Cookie cookie, Cancellable? cancellable = null) throws Error
Asynchronously delete a Cookie from the current session.
When the operation is finished, callback will be called. You can then call delete_cookie.end to get 
      the result of the operation.
Parameters:
| this | |
| cookie | the Cookie to be deleted | 
| cancellable | a Cancellable or null to ignore | 
| callback | a TaskReadyCallback to call when the request is satisfied | 
| user_data | the data to pass to callback function |