enhance: keep consistent of memory and meta of broadcaster

[chyezh]

issue: #38399
pr: #39720

[mergify]

@chyezh go-sdk check failed, comment rerun go-sdk can trigger the job again.

[codecov]

Codecov Report

Attention: Patch coverage is 98.21429% with 1 line in your changes missing coverage. Please review.

Project coverage is 81.03%. Comparing base (4a8e6fc) to head (6bb69c6).
Report is 1 commits behind head on 2.5.

Files with missing lines	Patch %	Lines
...treamingcoord/server/broadcaster/broadcast_task.go	98.21%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##              2.5   #39721   +/-   ##
=======================================
  Coverage   81.02%   81.03%           
=======================================
  Files        1415     1415           
  Lines      198870   198889   +19     
=======================================
+ Hits       161138   161164   +26     
- Misses      32066    32067    +1     
+ Partials     5666     5658    -8     

Components	Coverage Δ
Client	78.26% <ø> (ø)
Core	69.46% <ø> (ø)
Go	82.99% <98.21%> (+<0.01%)	⬆️

Files with missing lines	Coverage Δ
...treamingcoord/server/broadcaster/broadcast_task.go	95.74% <98.21%> (+0.66%)	⬆️

... and 30 files with indirect coverage changes

[chyezh]

rerun ut

[chyezh]

run go-sdk

[jaime0815]

/lgtm

[sre-ci-robot]

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