@Override
    public boolean isParallel() {
        return inner.isParallel();
    }
Returns whether this stream, if a terminal operation were to be executed,
would execute in parallel.  Calling this method after invoking an
terminal stream operation method may yield unpredictable results.

@return {@code true} if this stream would execute in parallel if executed
common-parent/mapstream/src/main/java/com/speedment/common/mapstream/MapStream.java