_metcd/etcd_store.go
func (s *etcdStore) applyInternalRaftRequest(req etcdserverpb.InternalRaftRequest) (proto.Message, error) {
	switch {
	case req.Range != nil:
		return applyRange(noTxn, s.kv, req.Range)
	case req.Put != nil:
		return applyPut(noTxn, s.kv, s.lessor, req.Put)
	case req.DeleteRange != nil:
		return applyDeleteRange(noTxn, s.kv, req.DeleteRange)
	case req.Txn != nil:
		return applyTransaction(s.kv, s.lessor, req.Txn)
	case req.Compaction != nil:
		return applyCompaction(s.kv, req.Compaction)
	case req.LeaseGrant != nil:
		return applyLeaseGrant(s.lessor, req.LeaseGrant)
	case req.LeaseRevoke != nil:
		return applyLeaseRevoke(s.lessor, req.LeaseRevoke)
	default:
		return nil, fmt.Errorf("internal Raft request type not implemented")
	}
}
func (s *etcdStore) applyInternalRaftRequest(req etcdserverpb.InternalRaftRequest) (proto.Message, error) {
	switch {
	case req.Range != nil:
		return applyRange(noTxn, s.kv, req.Range)
	case req.Put != nil:
		return applyPut(noTxn, s.kv, s.lessor, req.Put)
	case req.DeleteRange != nil:
		return applyDeleteRange(noTxn, s.kv, req.DeleteRange)
	case req.Txn != nil:
		return applyTransaction(s.kv, s.lessor, req.Txn)
	case req.Compaction != nil:
		return applyCompaction(s.kv, req.Compaction)
	case req.LeaseGrant != nil:
		return applyLeaseGrant(s.lessor, req.LeaseGrant)
	case req.LeaseRevoke != nil:
		return applyLeaseRevoke(s.lessor, req.LeaseRevoke)
	default:
		return nil, fmt.Errorf("internal Raft request type not implemented")
	}
}
// From committed entryc, back to public API method.
// etcdserver/v3demo_server.go applyV3Result