fix high CPU usage in mesh (close #319)

[localvar]

Before the change, when the register attempt (call to routine) succeeds, it enters the next iteration immediately.
The fix inserts a wait between each register attempt.

[megaeasex]

[TASK:easegress-pr-test SUCCESS]megaease/easegress Pull Request 322 Deploy Test Success

[codecov-commenter]

Codecov Report

Merging #322 (915d468) into main (465736c) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #322   +/-   ##
=======================================
  Coverage   80.23%   80.23%           
=======================================
  Files          53       53           
  Lines        6098     6098           
=======================================
  Hits         4893     4893           
  Misses        943      943           
  Partials      262      262           

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[haoel]

can we explain why the CPU is high and why this fix works?

[localvar]

can we explain why the CPU is high and why this fix works?

Before the change, when the register attempt (call to routine) succeeds, it enters the next iteration immediately.
The fix inserts a wait between each register attempt.

[suchen-sci]

This change is great! LGTM!