feat: transformer function struct

[xdlbdy]

What problem does this PR solve?

Issue Number: close #xxx

Problem Summary

What is changed and how does it work?

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

[codecov]

Codecov Report

Merging #357 (11a427d) into main (09f3748) will decrease coverage by 0.12%.
The diff coverage is 60.11%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #357      +/-   ##
==========================================
- Coverage   62.72%   62.60%   -0.13%     
==========================================
  Files         133      159      +26     
  Lines       12128    13356    +1228     
==========================================
+ Hits         7607     8361     +754     
- Misses       3977     4407     +430     
- Partials      544      588      +44     

Impacted Files	Coverage Δ
internal/controller/eventbus/block/block.go	56.09% <0.00%> (ø)
internal/controller/eventbus/server/instance.go	72.04% <ø> (ø)
internal/controller/trigger/storage/secret.go	48.48% <ø> (ø)
...nternal/controller/trigger/storage/subscription.go	54.71% <ø> (ø)
...ernal/controller/trigger/storage/trigger_worker.go	63.41% <ø> (ø)
...rnal/primitive/interceptor/errinterceptor/error.go	0.00% <0.00%> (ø)
.../primitive/interceptor/memberinterceptor/member.go	0.00% <0.00%> (ø)
internal/primitive/vanus/id.go	19.68% <0.00%> (-0.65%)	⬇️
internal/raft/log/wal.go	100.00% <ø> (ø)
internal/store/block/raft/appender.go	0.00% <0.00%> (ø)
... and 95 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 4ed721d...11a427d. Read the comment docs.

[wenfengwang]

LGTM