code: @SafeVarargs
      public static String[] addAll(final String[] a, final String... b) {
          if (N.isNullOrEmpty(a)) {
              return N.isNullOrEmpty(b) ? N.EMPTY_STRING_ARRAY : b.clone();
          }
  
          final String[] newArray = new String[a.length + b.length];
  
          copy(a, 0, newArray, 0, a.length);
          copy(b, 0, newArray, a.length, b.length);
  
          return newArray;
      }
docs: <p>
  Adds all the elements of the given arrays into a new array.
  </p>
  
  @param a
  the first array whose elements are added to the new array.
  @param b
  the second array whose elements are added to the new array.
  @return A new array containing the elements from a and b