code: @Nonnull
    public static EChange setUseSTARTTLS (final boolean bUseSTARTTLS)
    {
      return s_aRWLock.writeLocked ( () -> {
        if (s_bUseSTARTTLS == bUseSTARTTLS)
          return EChange.UNCHANGED;
        s_bUseSTARTTLS = bUseSTARTTLS;
        return EChange.CHANGED;
      });
    }
docs: Use STARTTLS by default?
  
  @param bUseSTARTTLS
  <code>true</code> to use it by default, <code>false</code> if not.
  @return {@link EChange}