Provide the size of exported chat history data

[poliandro]

Is your feature request related to a problem?

When exporting chat history users should know in advance the size of the exported data, so they can assure they have enough storage space to save the data.

Describe the solution you'd like

Provide size of the exported data before the backup process begins.

Describe alternatives you've considered

#25810 Resume export from where it stopped last time.

Additional context

The export feature is fundamental to users interaction with Telegram, because it allows them to backup their data, but it has many issues and lacks many features. It has no resume option so if is interrupted it starts all over again from the beginning. It scans all messages from the oldest to newest even if the user has selected a narrow time period. It lacks the option to export only the own user messages. It has low speed that makes the export process painfully difficult. It doesn't have an automatic or scheduled option. It is missing an incremental export feature. Doesn't have more granular control over time period.

I like Telegram, but the export feature is frustrating to use. Please make the experience more rich, fast and easy to use. Thank you!