[JAV-483]Optimize asynchronous heartbeat api

[little-cui]

No description provided.

[coveralls]

Coverage decreased (-0.2%) to 70.014% when pulling 4e42d2f on little-cui:master into e008a5d on ServiceComb:master.

[codecov-io]

Codecov Report

Merging #155 into master will increase coverage by 0.04%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #155      +/-   ##
==========================================
+ Coverage   65.81%   65.86%   +0.04%     
==========================================
  Files          18       18              
  Lines        4423     4423              
==========================================
+ Hits         2911     2913       +2     
+ Misses       1328     1326       -2     
  Partials      184      184

Impacted Files	Coverage Δ
server/service/rule.go	71.51% <0%> (-0.3%)	⬇️
server/service/governservice.go	72.92% <0%> (+1.08%)	⬆️

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[coveralls]

Coverage remained the same at 70.171% when pulling 9ff5ca6 on little-cui:master into e008a5d on ServiceComb:master.

[coveralls]

Coverage decreased (-0.05%) to 70.124% when pulling 9ff5ca6 on little-cui:master into e008a5d on ServiceComb:master.