code: @Nonnull
    public final EChange setAddress (@Nonnull final String sAddress)
    {
      ValueEnforcer.notNull (sAddress, "Address");
  
      final String sRealAddress = EmailAddressHelper.getUnifiedEmailAddress (sAddress);
      if (EqualsHelper.equals (sRealAddress, m_sAddress))
        return EChange.UNCHANGED;
  
      // Check only without MX record check here, because this is a performance
      // bottleneck when having multiple customers
      if (sRealAddress != null && !EmailAddressHelper.isValid (sRealAddress))
      {
        if (LOGGER.isErrorEnabled ())
          LOGGER.error ("Found an illegal email address: '" + sRealAddress + "'");
        return EChange.UNCHANGED;
      }
      m_sAddress = sRealAddress;
      return EChange.CHANGED;
    }
docs: Set the address part of the email address. Performs a validity check of the
  email address.
  
  @param sAddress
  The address part to be set. May not be <code>null</code>.
  @return {@link EChange#CHANGED} if the address was valid and different from
  the existing one. Returns {@link EChange#UNCHANGED} if the email
  address was the same as before, or the email address itself was
  invalid.