docs: public Len rdbLoadLen() throws IOException {
          boolean isencoded = false;
          int rawByte = in.read();
          int type = (rawByte & 0xC0) >> 6;
          long value;
          if (type == RDB_ENCVAL) {
              isencoded = true;
              value = rawByte & 0x3F;
          } else if (type == RDB_6BITLEN) {
              value = rawByte & 0x3F;
          } else if (type == RDB_14BITLEN) {
              value = ((rawByte & 0x3F) << 8) | in.read();
          } else if (rawByte == RDB_32BITLEN) {
              value = in.readInt(4, false);
          } else if (rawByte == RDB_64BITLEN) {
              value = in.readLong(8, false);
          } else {
              throw new AssertionError("unexpected len-type:" + type);
          }
          return new Len(value, isencoded);
      }