Vim Plugin crashing Extension Host

Describe the bug
Vim extension crashes the extension host. I initially thought it was a VSCode issue (e.g. https://github.com/microsoft/vscode/issues/114714), but this has persisted through several months of VSCode upgrades. I ran the Extension Bisect program and it points out this extension as the culprit for why the extension host is crashing.

I've used this extension for a few years with no issue, but in the past few months it seems to bring down VSCode regularly.

To Reproduce
Steps to reproduce the behavior:

1. Use the extension for 10-15 minutes
2. See extension host crash

(I don't have a better repro because it just happens no matter what I do)

Expected behavior
To use this extension without it crashing every 10-15 minutes.

Environment (please complete the following information):

• Extension (VsCodeVim) version: 1.21.5
  VSCode Version: 1.58.0
  Commit: 2d23c42a936db1c7b3b06f918cde29561cc47cd6
  Date: 2021-07-08T06:54:17.694Z (1 wk ago)
  Electron: 12.0.13
  Chrome: 89.0.4389.128
  Node.js: 14.16.0
  V8: 8.9.255.25-electron.0
  OS: Darwin x64 20.3.0

Additional context
Add any other context about the problem here.

Start by reproducing the crash with VSCodeVim 1.21.5 and the reported VS Code environment, then use Extension Bisect and Developers: Show Running Extensions to gather evidence. The issue provides no source file or test entry point and says the crash occurs after 10–15 minutes without a reliable trigger; done means the extension host no longer crashes during that usage.