Function deltachat::receive_imf::get_parent_message

async fn get_parent_message(
    context: &Context,
    references: Option<&str>,
    in_reply_to: Option<&str>
) -> Result<Option<Message>>

Returns the last message referenced from References: header found in the database.

If none found, tries In-Reply-To: as a fallback for classic MUAs that don’t set the References: header.