You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: state.go
    path of file: ./repos/td/telegram/updates
    
    the code of the file until where you have to start completion: package updates

import (
	"context"
	"fmt"
	"time"

	"github.com/go-faster/errors"
	"go.opentelemetry.io/otel/trace"
	"go.uber.org/zap"
	"golang.org/x/sync/errgroup"

	"github.com/gotd/td/telegram"
	"github.com/gotd/td/tg"
)

const (
	idleTimeout    = time.Minute * 15
	fastgapTimeout = time.Millisecond * 500

	diffLimitUser = 100
	diffLimitBot  = 100000
)

type tracedUpdate struct {
	update tg.UpdatesClass
	span   trace.SpanContext
}

type internalState struct {
	// Updates channel.
	externalQueue chan tracedUpdate

	
    
func (s *internalState) handleSeq(ctx context.Context, u *tg.UpdatesCombined) error {
	ctx, span := s.tracer.Start(ctx, "handleSeq")
	defer span.End()

	if err := validateSeq(u.Seq, u.SeqStart); err != nil {
		s.log.Error("Seq validation failed", zap.Error(err), zap.Any("update", u))
		return nil
	}

	// Special case.
	if u.Seq == 0 {
		ptsChanged, err := s.applyCombined(ctx, u)
		if err != nil {
			return err
		}

		if ptsChanged {
			return s.getDifference(ctx)
		}

		return nil
	}

	return s.seq.Handle(ctx, update{
		Value: u,
		State: u.Seq,
		Count: u.Seq - u.SeqStart + 1,
	})
}