<prompt> Translate the following text to SwahiliIf desired, having one carrier would allow the maintenance of the mailbox rule with, as discussed above, a reduction in competitive pressure, which in turn would be helpful in protecting the mail.  <response>: Ikiwa inahitajika, kuwa na mtoa huduma mmoja itaruhusu kudumisha sheria ya sanduku la barua kwa, kama ilivyojadiliwa hapo juu, kupunguzwa kwa shinikizo la ushindani, ambayo kwa upande wake ingekuwa muhimu katika kulinda barua. 