code: function getLengthEncoding(n, special) {
    if(n < 0) throw new Error('Cannot write negative length encoding: ' + n);
    if(!special) {
      if(n <= 0x3F) {
        return new Buffer([n]);
      }else if (n <= 0x3FFF) {
        return new Buffer([0x40 | (n >> 8), n & 0xFF]);
      }else if (n <= 0xFFFFFFFF) {
        var buffer = new Buffer(5);
        buffer.writeUInt8(0x80, 0);
        buffer.writeUInt32BE(n, 1);
        return buffer;
      }
      throw new Error('Failed to write length encoding: ' + n);
    }else{
      if (n > 0x3F) {
        throw new Error('Cannot encode ' + n + ' using special length encoding');
      }
      return new Buffer([0xC0 | n]);
    }
  }
docs: Get a buffer with the length encoding.