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/transport/connection_test.go

@@ -0,0 +1,51 @@
+package transport
+
+import (
+	"bytes"
+	"context"
+	"net"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/bin"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/proto/codec"
+)
+
+func TestConnection(t *testing.T) {
+	leftConn, rightConn := net.Pipe()
+	intermediate := codec.Intermediate{}
+
+	left := connection{
+		conn:  leftConn,
+		codec: intermediate,
+	}
+	right := connection{
+		conn:  rightConn,
+		codec: intermediate,
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
+	defer cancel()
+
+	buf := bytes.Repeat([]byte{1, 2, 3, 4}, 50)
+	done := make(chan []byte)
+	go func() {
+		defer close(done)
+
+		var b bin.Buffer
+		if err := right.Recv(ctx, &b); err != nil {
+			t.Error(err)
+			return
+		}
+
+		done <- b.Buf
+	}()
+
+	if err := left.Send(ctx, &bin.Buffer{Buf: buf}); err != nil {
+		t.Fatal(err)
+	}
+
+	require.Equal(t, buf, <-done)
+}