code: @Nonnull
    public static ESuccess sleep (@Nonnegative final long nDuration, @Nonnull final TimeUnit aTimeUnit)
    {
      ValueEnforcer.isGE0 (nDuration, "Duration");
      ValueEnforcer.notNull (aTimeUnit, "TimeUnit");
  
      return sleep (aTimeUnit.toMillis (nDuration));
    }
docs: Sleep the current thread for a certain amount of time
  
  @param nDuration
  The duration to sleep. Must be &ge; 0.
  @param aTimeUnit
  The time unit to use. May not be <code>null</code>.
  @return {@link ESuccess#SUCCESS} if sleeping was not interrupted,
  {@link ESuccess#FAILURE} if sleeping was interrupted