An asynchronous sequence that contains one or more incoming attachment
containers for you to process.
After a participant uploads a file or data, the system makes that content available
on the ``Attachments`` asynchronous sequence of each session participant.
Configure an asynchronous task to monitor this sequence and process
results when they arrive.
The following example shows you how to configure this task and use it to
iterate over the available items. The `journal` variable
contains a previously configured ``GroupSessionJournal`` object.
```
let attachmentListener = Task {
for await attachments in journal.attachments {
for attachment in attachments {
// Download and process each attachment.
}
}
}
```
Creates the asynchronous iterator that produces elements of
this asynchronous sequence.
-Returns: An instance of the `Iterator` type that produces
elements of the asynchronous sequence.