feat: support custom highWaterMark

[fengmk2]

closes https://github.com/node-modules/urllib/issues/435

[codecov[bot]]

Codecov Report

Merging #450 (eae98ec) into master (d4e5f39) will increase coverage by 0.00%. The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #450   +/-   ##
=======================================
  Coverage   99.51%   99.51%           
=======================================
  Files           8        8           
  Lines        1243     1246    +3     
  Branches      240      241    +1     
=======================================
+ Hits         1237     1240    +3     
  Misses          6        6           

Impacted Files	Coverage Δ
src/HttpClient.ts	99.51% <100.00%> (+<0.01%)	:arrow_up:
src/Request.ts	100.00% <100.00%> (ø)

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[github-actions[bot]]

:tada: This PR is included in version 3.16.0 :tada:

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot :package::rocket: