code: public static <S extends Seq<S>> S concatenate(S... sequences) {
          if (sequences.length == 0)
              throw new IllegalArgumentException("Zero arguments");
  
          if (sequences.length == 1)
              return sequences[0];
  
          int size = 0;
          for (S s : sequences)
              size += s.size();
  
          SeqBuilder<S> builder = sequences[0].getBuilder().ensureCapacity(size);
  
          for (S s : sequences)
              builder.append(s);
  
          return builder.createAndDestroy();
      }
docs: Returns a concatenation of several sequences.
  
  @param sequences array of sequences
  @param <S>       type of sequences
  @return concatenation of several sequences