code: @Deprecated
    public static <T> Collection<T> concat(Collection<? extends T> left,
        Collection<? extends T> right) {
      return new ConcattedCollectionView<T>(left, right);
    }
docs: Returns a view of the concatenation of the two provided collections. Iterating through this
  view will provide all the elements of {@code left} according to its own iteration order,
  followed by the elements of {@code right} according to its.  The size of this collection view
  is the sum of the sizes of {@code left} and {@code right}.
  
  Equality and hashCode on a concatted view are undefined.
  
  @deprecated For almost all purposes you should jsut prefer {@link com.google.common.collect.FluentIterable#append(Iterable)}
  or {@link com.google.common.collect.Iterables#concat(Iterable[])}.