callback for async task waiter

[vlboiko]

Description

Brief description of what this PR does.

Type of Change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Code refactoring (no functional changes)
• Performance improvement
• Test coverage improvement

Changes Made

Testing

• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have tested the examples affected by my changes

Documentation

• I have updated the documentation accordingly
• I have updated the CHANGELOG.md (if applicable)
• My changes generate no new warnings in the documentation build

Code Quality

• My code follows the Go style guidelines
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new lint warnings
• I have run make fmt and make lint locally

Breaking Changes

If this PR contains breaking changes, please describe them here and how users should adapt their code:

Additional Notes

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Related Issues

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Closes #(issue number)
Relates to #(issue number)

[coveralls]

Pull Request Test Coverage Report for Build 18919892608

Details

• 146 of 249 (58.63%) changed or added relevant lines in 42 files are covered.
• 11 unchanged lines in 3 files lost coverage.
• Overall coverage increased (+0.8%) to 5.472%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
resources/typed/blockhostmapping_autogen.go	0	1	0.0%
resources/typed/cbox_autogen.go	0	1	0.0%
resources/typed/dnode_autogen.go	0	1	0.0%
resources/typed/eventdefinition_autogen.go	0	1	0.0%
resources/typed/host_autogen.go	0	1	0.0%
resources/typed/protectedpath_autogen.go	0	1	0.0%
resources/typed/supportbundles_autogen.go	0	1	0.0%
resources/typed/tenant_autogen.go	0	1	0.0%
resources/typed/user_autogen.go	0	1	0.0%
resources/typed/view_autogen.go	0	1	0.0%

Files with Coverage Reduction	New Missed Lines	%
core/utils.go	2	56.55%
resources/untyped/v_task.go	3	0.0%
openapi_schema/api.go	6	29.47%

Totals
Change from base Build 18896441878:	0.8%
Covered Lines:	1107
Relevant Lines:	20229

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💛 - Coveralls