title: Telegram bot api: Error code 429, Error: Too many requests: retry later
body: <p>We have a Telegram bot. It has around 1.2 million subscribers.</p>
  <p>Now we're facing a problem in sending messages to these number of subscribers.</p>
  <p>Telegram bot API does not provide any batch message functionality and we'd have to send individual requests to Telegram. The problem is, after a few thousand messages, Telegram starts responding with Error 429: too many requests, and does not accept any requests for a while.</p>
  <p>How can we effectively message our subscribers?</p>