code: private static void getNextBranchChars(CharSequence chars, int pos, int length, Appendable out) {
          while(length>kMaxBranchLinearSubNodeLength) {
              ++pos;  // ignore the comparison unit
              getNextBranchChars(chars, jumpByDelta(chars, pos), length>>1, out);
              length=length-(length>>1);
              pos=skipDelta(chars, pos);
          }
          do {
              append(out, chars.charAt(pos++));
              pos=skipValue(chars, pos);
          } while(--length>1);
          append(out, chars.charAt(pos));
      }
docs: getNextChars() when pos is on a branch node.