[ Version ( since = "3.44" ) ]
public async bool contains_email (string email_address, Cancellable? cancellable) throws Error
Asynchronously checks whether contains an email_address.
When the email_address contains multiple addresses, then returns true when at least one
address exists in the address book.
When the operation is finished, callback will be called. You can then call contains_email.end to
get the result of the operation.
| this |
an BookBackend |
| email_address |
an email address |
| cancellable |
optional Cancellable object, or null |
| callback |
a TaskReadyCallback to call when the request is satisfied |
| user_data |
data to pass to the callback function |