public long readRawLittleEndian64() throws IOException {
        final byte[] bs = new byte[8];
        nioBuffer.get(bs);

        return (((long) bs[0] & 0xff)) | (((long) bs[1] & 0xff) << 8) | (((long) bs[2] & 0xff) << 16)
               | (((long) bs[3] & 0xff) << 24) | (((long) bs[4] & 0xff) << 32) | (((long) bs[5] & 0xff) << 40)
               | (((long) bs[6] & 0xff) << 48) | (((long) bs[7] & 0xff) << 56);
    }
Read a 64-bit little-endian integer from the internal byte buffer.
jraft-rheakv/rheakv-core/src/main/java/com/alipay/sofa/jraft/rhea/serialization/impl/protostuff/io/NioBufInput.java