# Objective
- Allow to configure `on_thread_spawn` and `on_thread_destroy` when
using `TaskPoolPlugin` of bevy.
## Solution
- In `TaskPoolThreadAssignmentPolicy`, two options `on_thread_spawn` and
`on_thread_destroy` are added, which will be passed to two new methods
motioned above when creating corresponding task pool using builder.
- Due to lack of debug derive for these two options, manually implement
the debug for `TaskPoolThreadAssignmentPolicy`.
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## Changelog
### Added
- `on_thread_spawn` option and `on_thread_destroy` option to the
`TaskPoolPlugin`, allow user to customize them as needed.
## Migration Guide
- `TaskPooolThreadAssignmentPolicy` now has two additional fields:
`on_thread_spawn` and `on_thread_destroy`. Please consider defaulting
them to `None`.
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Co-authored-by: François Mockers <mockersf@gmail.com>
Co-authored-by: François Mockers <francois.mockers@vleue.com>