fix(cache, proxy, response): avoid sending handled events

[pi0]

When event is handled, utils should early return and avoid calling node.res.end

[codecov]

Codecov Report

Merging #411 (4dceb6f) into main (5b9a2f0) will decrease coverage by 1.99%.
The diff coverage is 42.85%.

@@            Coverage Diff             @@
##             main     #411      +/-   ##
==========================================
- Coverage   76.65%   74.66%   -1.99%     
==========================================
  Files          26       26              
  Lines        2480     2491      +11     
  Branches      355      353       -2     
==========================================
- Hits         1901     1860      -41     
- Misses        579      631      +52     

Impacted Files	Coverage Δ
src/utils/cache.ts	27.77% <0.00%> (-1.07%)	⬇️
src/utils/response.ts	62.61% <50.00%> (-0.24%)	⬇️
src/utils/proxy.ts	83.33% <60.00%> (-0.59%)	⬇️

... and 3 files with indirect coverage changes