deltachat::receive_imf

Function get_to_and_past_contact_ids

Source 
async fn get_to_and_past_contact_ids(
    context: &Context,
    mime_parser: &MimeMessage,
    chat_assignment: &ChatAssignment,
    is_partial_download: Option<u32>,
    parent_message: &Option<Message>,
    incoming_origin: Origin,
) -> Result<(Vec<Option<ContactId>>, Vec<Option<ContactId>>)>