move gotd fork into repo. (#111)

- update to latest telegram layer
- remove some references to fields in tg.Entities that don't exist in
the schema
- originally added here:
https://github.com/beeper/td/commit/820929062a2ba0104397bc01235ab58a9cff780e
  - referenced here
-
https://github.com/mautrix/telegramgo/commit/124f0967ed195b5a380c9bd02e170ada9710dde3
-
https://github.com/mautrix/telegramgo/commit/4205047aab2e0639217148b5d125bfaab668bd8e

pkg/gotd/exchange/fuzz_test.go

@@ -0,0 +1,67 @@
+//go:build go1.18
+
+package exchange
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"go.uber.org/zap"
+	"golang.org/x/sync/errgroup"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/testutil"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/transport"
+)
+
+func FuzzValid(f *testing.F) {
+	f.Add([]byte{1, 2, 3})
+	f.Fuzz(func(t *testing.T, data []byte) {
+		const dc = 2
+		reader := testutil.Rand(data)
+		privateKey := PrivateKey{
+			RSA: testutil.RSAPrivateKey(),
+		}
+
+		config := zap.NewProductionConfig()
+		config.OutputPaths = []string{"stdout"}
+		log, err := config.Build()
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		i := transport.Intermediate
+		client, server := i.Pipe()
+
+		ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
+		defer cancel()
+
+		g, gctx := errgroup.WithContext(ctx)
+		g.Go(func() error {
+			_, err := NewExchanger(client, dc).
+				WithLogger(log.Named("client")).
+				WithRand(reader).
+				Client([]PublicKey{privateKey.Public()}).
+				Run(gctx)
+			if err != nil {
+				cancel()
+			}
+			return err
+		})
+		g.Go(func() error {
+			_, err := NewExchanger(server, dc).
+				WithLogger(log.Named("server")).
+				WithRand(reader).
+				Server(privateKey).
+				Run(gctx)
+			if err != nil {
+				cancel()
+			}
+			return err
+		})
+
+		if err := g.Wait(); err != nil {
+			t.Fatal(err)
+		}
+	})
+}