code: public static MutableList<String> chunk(String string, int size)
      {
          if (size <= 0)
          {
              throw new IllegalArgumentException("Size for groups must be positive but was: " + size);
          }
  
          int length = string.length();
  
          if (length == 0)
          {
              return FastList.newList();
          }
  
          MutableList<String> result = FastList.newList((length + size - 1) / size);
  
          int startOffset = 0;
          while (startOffset < length)
          {
              result.add(string.substring(startOffset, Math.min(startOffset + size, length)));
              startOffset += size;
          }
  
          return result;
      }
docs: Partitions String in fixed size chunks.
  
  @param size the number of characters per chunk
  @return A {@code MutableList} containing {@code String}s of size {@code size}, except the last will be
  truncated (i.e. shorter) if the characters don't divide evenly.
  @since 5.2