What is Drupal Big Pipe?

Drupal included a module in core called Big Pipe. The Big Pipe concept is about loading page data as it becomes available instead of waiting for the entire response before showing anything. This will not affect the total response time, but will greatly reduce the perceived response time. The page will appear to load faster and portions of the content can be readable in less time. Below is a video showing the perceived speed of Big Pipe. Page data is displayed as it becomes ready, and placeholders are created for sidebar items that will be filled in as the data is available. This caching improvement applies to authenticated users viewing pages that have partially customized content.

    Refer: https://www.youtube.com/watch?v=JwzX0Qv6u3A