normalize_contact_async
Description:
[ Version ( since = "0.23.1" ) ]
public async string normalize_contact_async (string contact, Cancellable? cancellable) throws Error
  public async string normalize_contact_async (string contact, Cancellable? cancellable) throws Error
Perform best-effort offline contact normalization.
This does syntactic normalization (e.g. transforming case-insensitive text to lower-case), but does not query servers or anything similar.
Parameters:
| this | a protocol | 
| contact | a contact identifier, possibly invalid | 
| cancellable | may be used to cancel the async request | 
| callback | a callback to call when the request is satisfied | 
| user_data | data to pass to  |