@Override
    public int hashCode() {
        return Objects.hash(dataBytes, entriesCount, meta, prevLogIndex, prevLogTerm);
    }
RpcRequestHeader class supports both AppendEntriesRequest and SnapshotMeta headers.
It keeps the request metadata info without the data, designed to reduce memory consumption for RPC.
This class provides constructors for handling metadata from both types of requests.
@author dennis
jraft-core/src/main/java/com/alipay/sofa/jraft/core/RpcRequestHeader.java