Simultaneous typing fails for two or more users

To reproduce:

Open the same page with two different users.
Attempt to type at exactly the same time.
Observe that when they type at exactly the same time, characters are rejected or inserted into the wrong place.

Reason:

When a user's session receives a patch at the same moment that it attempts to send a patch, operational transform is applied to reconcile the differences.

This process is prone to failure, and results in at least one of the patches being rejected. As a result, it is difficult for two or more users to type simultaneously.