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/uploader/upload.go

@@ -0,0 +1,77 @@
+// Package uploader contains uploading files helpers.
+package uploader
+
+import (
+	"io"
+	"sync"
+
+	"go.uber.org/atomic"
+)
+
+// NewUpload creates new Upload struct using given
+// name and reader.
+func NewUpload(name string, from io.Reader, total int64) *Upload {
+	return &Upload{
+		name:       name,
+		totalBytes: total,
+		from:       from,
+		partSize:   -1,
+	}
+}
+
+// Upload represents Telegram file upload.
+type Upload struct {
+	// Fields which will be set by Uploader.
+	// File ID for Telegram.
+	id int64
+	// Sent parts (in partSize).
+	sentParts atomic.Int64
+
+	// Confirmed uploaded parts.
+	confirmedParts int
+	// Confirmed uploaded bytes.
+	confirmedBytes int64
+	confirmedMux   sync.Mutex
+
+	// Total parts.
+	totalParts int
+	// Part size of uploader.
+	partSize int
+	// Flag to determine class of size of file.
+	big bool
+
+	// Total size (in bytes) of upload.
+	totalBytes int64 // immutable
+	// Name of file.
+	name string // immutable
+	// Reader of data.
+	from io.Reader // immutable
+}
+
+func (u *Upload) confirmSmall(bytes int) ProgressState {
+	u.confirmedMux.Lock()
+	defer u.confirmedMux.Unlock()
+
+	u.confirmedParts++
+	return u.confirmLocked(u.confirmedParts, bytes)
+}
+
+func (u *Upload) confirm(part, bytes int) ProgressState {
+	u.confirmedMux.Lock()
+	defer u.confirmedMux.Unlock()
+
+	return u.confirmLocked(part, bytes)
+}
+
+func (u *Upload) confirmLocked(part, bytes int) ProgressState {
+	u.confirmedBytes += int64(bytes)
+
+	return ProgressState{
+		ID:       u.id,
+		Name:     u.name,
+		Part:     part,
+		PartSize: u.partSize,
+		Uploaded: u.confirmedBytes,
+		Total:    u.totalBytes,
+	}
+}