// healthy, when the leader is stopped, the leadership transfer should be
	// smooth. (leader transfers its leadership before stopping). If leader is
	// hard killed, other servers will take an election timeout to realize
	// leader lost and start campaign.
	return clientv3.WithRequireLeader(ctx)
}

func (s *store) getCurrentState(ctx context.Context, key string, v reflect.Value, ignoreNotFound bool) func() (*objState, error) {

Sem um sistema de validação de dados, você teria que realizar todas as verificações manualmente, no código.

Esses recursos são o que Marshmallow foi construído para fornecer. Ele é uma ótima biblioteca, e eu já utilizei muito antes.

	// the same type flag but has a completely different layout.
	if blk.getFormat() != FormatGNU {
		return nil, ErrHeader
	}
	hdr.Format.mayOnlyBe(FormatGNU)

	var p parser
	hdr.Size = p.parseNumeric(blk.toGNU().realSize())
	if p.err != nil {
		return nil, p.err
	}
	s := blk.toGNU().sparse()
	spd := make(sparseDatas, 0, s.maxEntries())
	for {
		for i := 0; i < s.maxEntries(); i++ {

	// Because we overwrite the build action with the install action below,
	// a1 may already be an install action fetched from the "build" cache key,
	// and the caller just doesn't realize.
	if strings.HasSuffix(a1.Mode, "-install") {
		if a1.buggyInstall && mode == ModeInstall {
			//  Congratulations! The buggy install is now a proper install.
			a1.buggyInstall = false
		}
		return a1
	}

			if strict {
				// Cases #6 and #8: contradiction
				return false
			}

			// We're in case #5 or #7. Try to collapse path, and that will
			// fail if it realizes that we are in case #7.
			return po.collapsepath(n2, n1)
		}

		// We don't know of any existing relation between n1 and n2. They could
		// be part of the same DAG or not.

		select {
		case <-dialedc:
			dialed = true
		default:
		}

		if !tt.ok && dialed {
			t.Errorf("For key %q, value %q, transport dialed. Expected local failure. Response was: (%v, %v)\nServer replied with: %s", tt.key, tt.val, res, err, body)
		} else if (err == nil) != tt.ok {
			t.Errorf("For key %q, value %q; got err = %v; want ok=%v", tt.key, tt.val, err, tt.ok)
		}
	}
}

	curLoopIndex := curLoop - 1

	if len(r.forStack) == 1 {
		if loop.checkRet {
			list = append(list, r.ifNext(syntax.Eql, -1, false, retStmt(nil)))
		}
	} else {

		// Idealized check, implemented more simply for now.

		//	// N == depth of this loop, one less than the one just exited.
		//	if #next != 0 {
		//		if #next >= perLoopStep*N-1 { // this loop