save_to_callback

Saves this by feeding the produced data to save_func.

Can be used when you want to store the attachment to something other than a file, such as an in-memory buffer or a socket. If error is set, false will be returned. Possible errors include those in the FileError domain and whatever the save function generates.

Parameters:

this	A Attachment.
save_func	a function that is called to save each block of data that the save routine generates.
user_data	user data to pass to the save function.

Returns:

true, if the save successfully completed