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/tgerr/flood_wait_test.go

@@ -0,0 +1,57 @@
+package tgerr
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/gotd/neo"
+)
+
+func TestFloodWait(t *testing.T) {
+	floodWaitErr := New(400, ErrFloodWait)
+	floodWaitErr.Argument = 3600
+	ctx := context.Background()
+
+	t.Run("WrongType", func(t *testing.T) {
+		a := assert.New(t)
+
+		e := New(0, "wrong")
+		ok, err := FloodWait(ctx, e)
+		a.False(ok)
+		a.ErrorIs(err, e)
+	})
+	t.Run("Wait", func(t *testing.T) {
+		a := assert.New(t)
+		c := neo.NewTime(time.Now())
+		e := floodWaitErr
+
+		done := make(chan struct{})
+		observer := c.Observe()
+		go func() {
+			ok, err := FloodWait(ctx, e, FloodWaitWithClock(c))
+			a.True(ok)
+			a.ErrorIs(err, e)
+
+			close(done)
+		}()
+
+		<-observer
+		c.Travel(3601 * time.Second)
+		<-done
+	})
+	t.Run("ContextDone", func(t *testing.T) {
+		a := assert.New(t)
+		c := neo.NewTime(time.Now())
+		e := floodWaitErr
+
+		canceledCtx, cancel := context.WithCancel(ctx)
+		cancel()
+
+		ok, err := FloodWait(canceledCtx, e, FloodWaitWithClock(c))
+		a.False(ok)
+		a.ErrorIs(err, context.Canceled)
+	})
+}