@Override
    public LogEntryDecoder decoder() {
        return AutoDetectDecoder.INSTANCE;
    }
V2(Now) log entry codec implementation, header format:

  0  1     2    3  4  5
 +-+-+-+-+-+-+-+-++-+-+-+
 |Magic|Version|Reserved|
 +-+-+-+-+-+-+-+-++-+-+-+

@author boyan(boyan@antfin.com)
@since 1.2.6
jraft-core/src/main/java/com/alipay/sofa/jraft/entity/codec/v2/LogEntryV2CodecFactory.java