public static <T> SingletonStream<T> of(T element) {
        return new SingletonStream<>(element);
    }
Creates and returns an optimized sequential {@link Stream} implementation
with only a single element.

@param element the single element
@param <T> the type of the stream elements
@return a singleton sequential stream
common-parent/singletonstream/src/main/java/com/speedment/common/singletonstream/SingletonStream.java