# Objective
- I've been experimenting with different patterns to try and make async
tasks more convenient. One of the better ones I've found is to return a
command queue to allow for deferred &mut World access. It can be
convenient to check for task completion in a normal system, but it is
hard to do something with the command queue after getting it back. This
pr adds a `append` to Commands. This allows appending the returned
command queue onto the system's commands.
## Solution
- I edited the async compute example to use the new `append`, but not
sure if I should keep the example changed as this might be too
opinionated.
## Future Work
- It would be very easy to pull the pattern used in the example out into
a plugin or a external crate, so users wouldn't have to add the checking
system.
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## Changelog
- add `append` to `Commands` and `CommandQueue`
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