Swoosh.Adapter.deliver_many

You're seeing just the callback deliver_many, go back to Swoosh.Adapter module for more information.
Link to this callback

deliver_many(list, config)

View Source (optional)

Specs

deliver_many(
  [
    %Swoosh.Email{
      assigns: term(),
      attachments: term(),
      bcc: term(),
      cc: term(),
      from: term(),
      headers: term(),
      html_body: term(),
      private: term(),
      provider_options: term(),
      reply_to: term(),
      subject: term(),
      text_body: term(),
      to: term()
    }
  ],
  config()
) :: {:ok, term()} | {:error, term()}

Delivers multiple emails with the given config in one request. Some email providers allow multiple messages to be sent in one HTTP request, for example Mailjet allow this. Check your provider's documentation to see if that is possible.