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/pool/req_map_test.go

@@ -0,0 +1,39 @@
+package pool
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/tdsync"
+)
+
+func TestReqMap(t *testing.T) {
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+
+	g := tdsync.NewCancellableGroup(ctx)
+	req := newReqMap()
+
+	key, ch := req.request()
+	g.Go(func(ctx context.Context) error {
+		defer req.delete(key)
+
+		select {
+		case <-ch:
+			return nil
+		case <-ctx.Done():
+			return ctx.Err()
+		}
+	})
+
+	g.Go(func(ctx context.Context) error {
+		require.True(t, req.transfer(&poolConn{}))
+		require.False(t, req.transfer(&poolConn{}))
+		return nil
+	})
+
+	require.NoError(t, g.Wait())
+}