Investigate - slow typing

Description

Original report: https://github.com/mattermost/mattermost-server/issues/15012

Summary
Some people on the above linked Github issues have reported slow typing on Mattermost.
Also a few people from Mattermost staff have reported the same - see this thread in Ask R&D channel https://community.mattermost.com/core/pl/cgxsqhbxfffn38f8xoqfy38a9c.

Steps to reproduce
1. Start typing a message on Mattermost
2. Wait for text box to catch up with what was typed, sometimes 5+ seconds

Expected behavior
Expecting the message box to catch up with my typing with a delay less than 200 ms. The CPU is maxing out whenever I start typing. I can confirm this happens on Chromium as well, and both on Debian and Fedora on different devices.

QA Test Steps

None

Mana

None

Assignee

Unassigned

QA Assignee

None

Reporter

Amy Blais

Epic Link

None

Fix versions

Mattermost Team

Web Platform

Sprint

None

QA Testing Areas

None

GitHub Issue

None

Components

None

Severity

None