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/mtproto/new_encrypted_msg.go

@@ -0,0 +1,68 @@
+package mtproto
+
+import (
+	"github.com/go-faster/errors"
+	"go.uber.org/zap"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/bin"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/crypto"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/proto"
+)
+
+func (c *Conn) newEncryptedMessage(id int64, seq int32, payload bin.Encoder, b *bin.Buffer) error {
+	s := c.session()
+
+	// TODO(tdakkota): Smarter gzip.
+	// 	1) Generate Length() method for every encoder, to count length without encoding.
+	// 	2) Re-use buffer instead of using yet one.
+	// 	3) Do not send proto.GZIP if gzipped size is equal or bigger.
+	var (
+		d   crypto.EncryptedMessageData
+		log = c.log
+	)
+	if c.compressThreshold <= 0 {
+		if obj, ok := payload.(interface{ TypeID() uint32 }); ok {
+			log = c.logWithTypeID(obj.TypeID())
+		}
+		d = crypto.EncryptedMessageData{
+			SessionID: s.ID,
+			Salt:      s.Salt,
+			MessageID: id,
+			SeqNo:     seq,
+			Message:   payload,
+		}
+	} else {
+		payloadBuf := bufPool.Get()
+		defer bufPool.Put(payloadBuf)
+		if err := payload.Encode(payloadBuf); err != nil {
+			return errors.Wrap(err, "encode payload")
+		}
+
+		log = c.logWithType(payloadBuf)
+		if payloadBuf.Len() > c.compressThreshold {
+			d = crypto.EncryptedMessageData{
+				SessionID: s.ID,
+				Salt:      s.Salt,
+				MessageID: id,
+				SeqNo:     seq,
+				Message:   proto.GZIP{Data: payloadBuf.Raw()},
+			}
+		} else {
+			d = crypto.EncryptedMessageData{
+				SessionID:              s.ID,
+				Salt:                   s.Salt,
+				MessageID:              id,
+				SeqNo:                  seq,
+				MessageDataLen:         int32(payloadBuf.Len()),
+				MessageDataWithPadding: payloadBuf.Buf,
+			}
+		}
+	}
+
+	log.Debug("Request", zap.Int64("msg_id", id))
+	if err := c.cipher.Encrypt(s.Key, d, b); err != nil {
+		return errors.Wrap(err, "encrypt")
+	}
+
+	return nil
+}