code: @Nonnull
    public static ESuccess flush (@Nullable final Flushable aFlushable)
    {
      if (aFlushable != null)
        try
        {
          aFlushable.flush ();
          return ESuccess.SUCCESS;
        }
        catch (final NullPointerException ex)
        {
          // Happens if a java.io.FilterOutputStream is already closed!
        }
        catch (final IOException ex)
        {
          if (!isKnownEOFException (ex))
            LOGGER.error ("Failed to flush object " + aFlushable.getClass ().getName (),
                          ex instanceof IMockException ? null : ex);
        }
      return ESuccess.FAILURE;
    }
docs: Flush the passed object encapsulating the declared {@link IOException}.
  
  @param aFlushable
  The flushable to be flushed. May be <code>null</code>.
  @return {@link ESuccess#SUCCESS} if the object was successfully flushed.