file
Description:
For incoming file transfers, this property will be set to a File for the location where the file will be saved (given by accept_file_async) when the transfer starts.
The feature TP_FILE_TRANSFER_CHANNEL_FEATURE_CORE
must already be prepared for this property to have a meaningful value, and to
receive change notification. Once the initial value is set, this property will not be changed.
For outgoing file transfers, this property is a File for the location of the file being
sent (given by provide_file_async). The
feature TP_FILE_TRANSFER_CHANNEL_FEATURE_CORE
does not have to be prepared and there is no change notification.