Is there an existing issue for this?

• I did not find any existing issues.

Current Behavior

The bug happens when an enderio fluid tank is getting filled and emptied at the same time. During this time, if a player saves and quits, and alt + tab during the world saving process, world saving will hang infinitely. The game is effectively soft-locked.
The bug does not happen when the enderio fluid tank is full.

Expected Behavior

World save should not hang under any circumstance.

How to Test

1. Install Create and Enderio
2. Reproduce the setup shown in the picture below
3. A fluid pump should pump fluids into the enderio fluid tank
4. Have a fluid conduit extract from the enderio fluid tank into a creative create fluid tank. This should create a situation where the enderio fluid tank is slowly filling up.
5. While the enderio fluid tank is filling up, save and quit
6. While the world is saving, alt + tab to minimize Minecraft. You have to be fast with this.
7. Wait 5 seconds outside of minecraft, now world saving should be hanging infinitely.
   This is very hard to reproduce with a minimal setup. It is easier to reproduce with multiple mods that will bloat and slow down the world saving process. In the video, I click outside of Minecraft to reproduce the same effect.

Local Environment

- **Operating System**: Windows 10
- **Java version**: openjdk 17.0.13
- **Minecraft Version**: 1.20.1
- **Version**: 6.2.11-beta
- **Other Mods**: Create 6.0.4 for mc1.20.1

Any Additional Information?

Bug also appears with Create 1.20.1 0.5.1j
I don't think this is limited to a compatibility with create

I regret to say that we no longer officially support Minecraft 1.20.1 - as such we will not be officially fixing this issue.

If any community member wishes to submit a pull request to address this issue, feel free to open a PR and we will review and merge it.

I will close outstanding 1.20.1 issues in a little while, to keep the issue list clear.

Thanks again for your report.