refactor: remove heartbeat and redesign http client interface

[crispgm]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 80.00000% with 11 lines in your changes missing coverage. Please review.

Project coverage is 83.99%. Comparing base (e120e65) to head (36e4112).
Report is 6 commits behind head on main.

Files with missing lines	Patch %	Lines
v2/http.go	67.64%	7 Missing and 4 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #93      +/-   ##
==========================================
+ Coverage   81.67%   83.99%   +2.31%     
==========================================
  Files          66       32      -34     
  Lines        1817      812    -1005     
==========================================
- Hits         1484      682     -802     
+ Misses        231       90     -141     
+ Partials      102       40      -62     

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