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/telegram/middleware_test.go

@@ -0,0 +1,74 @@
+package telegram
+
+import (
+	"context"
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/bin"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/tg"
+)
+
+func TestMiddlewareOrder(t *testing.T) {
+	var calls []int
+	call := func(i int) {
+		calls = append(calls, i)
+	}
+	_ = chainMiddlewares(
+		// Client.
+		InvokeFunc(func(ctx context.Context, input bin.Encoder, output bin.Decoder) error {
+			call(0)
+			return nil
+		}),
+		// First middleware (index = 0).
+		MiddlewareFunc(func(next tg.Invoker) InvokeFunc {
+			return func(ctx context.Context, input bin.Encoder, output bin.Decoder) error {
+				t.Log("First")
+				call(1)
+				defer call(-1)
+				return next.Invoke(ctx, input, output)
+			}
+		}),
+		// Second middleware (index = 1).
+		MiddlewareFunc(func(next tg.Invoker) InvokeFunc {
+			return func(ctx context.Context, input bin.Encoder, output bin.Decoder) error {
+				call(2)
+				defer call(-2)
+				return next.Invoke(ctx, input, output)
+			}
+		}),
+	).Invoke(context.Background(), nil, nil)
+	require.Equal(t, []int{1, 2, 0, -2, -1}, calls)
+}
+
+func ExampleMiddleware() {
+	invoker := InvokeFunc(func(ctx context.Context, input bin.Encoder, output bin.Decoder) error {
+		fmt.Println("invoke")
+		return nil
+	})
+	printMiddleware := func(message string) Middleware {
+		return MiddlewareFunc(func(next tg.Invoker) InvokeFunc {
+			return func(ctx context.Context, input bin.Encoder, output bin.Decoder) error {
+				fmt.Println(message, "(start)")
+				err := next.Invoke(ctx, input, output)
+				fmt.Println(message, "(end)")
+				return err
+			}
+		})
+	}
+
+	// Testing composed invoker.
+	_ = chainMiddlewares(invoker,
+		printMiddleware("first"),
+		printMiddleware("second"),
+	).Invoke(context.Background(), nil, nil)
+
+	// Output:
+	// first (start)
+	// second (start)
+	// invoke
+	// second (end)
+	// first (end)
+}